A step-by-step walkthrough of every input and output in the app, so you can build a clear, personalised picture of your retirement finances.
Isaac is a planning tool. It helps you explore different retirement scenarios and understand how your finances might look in the future. It does not tell you what to do, recommend any products, or replace the guidance of a qualified financial adviser.
The projections Isaac produces are estimates based on the numbers you enter and assumptions about the future (investment returns, inflation, tax rules). The future is uncertain, and actual outcomes will differ. Use Isaac to inform your thinking, not as a guarantee.
If you need personalised financial advice, please speak to a regulated financial adviser.
The short version
Isaac answers one question: "Will I have enough money when I stop working?"
You tell Isaac about your pensions, savings, and how you plan to spend in retirement. Isaac then runs a year-by-year projection from today until age 100, showing you how your money grows while you're working, and how it gets drawn down once you retire.
If your money runs out at age 82, you'll see that. If it lasts until 100+, you'll see that too. And if the answer isn't what you hoped for, you can experiment: what if you retired a year later? What if you saved an extra £50 a month? What if you spent a bit less? Isaac recalculates instantly every time you change something.
Isaac handles UK income tax (both England/Wales and Scotland), State Pension, multiple pension types, ISAs, property, inheritance, and a lot more. You don't need to understand any of it to get started. Enter the basics and Isaac does the rest.
Remember: Isaac is a planning tool, not financial advice. It shows you projections based on the assumptions you put in. It does not recommend products, strategies, or actions. If you need advice, speak to a qualified financial adviser.
The onboarding flow takes about 2 minutes
When you first open Isaac, a short setup flow asks for four things. Don't worry about being exact. Rough estimates are perfectly fine, and you can change everything later.
| Field | What it means | Guidance |
|---|---|---|
| Date of birth | Isaac uses your date of birth to calculate your current age and track it automatically over time. This is the starting point for your projection. | Select your actual date of birth. Isaac computes your age from this. |
| Target retirement age | The age you'd like to stop working. This is when Isaac switches from "saving" mode to "spending" mode in the projection. | The UK average is around 65. If you have no idea, put 67 (current State Pension age) and experiment later. |
| Field | What it means | Guidance |
|---|---|---|
| Current pension pot | How much is in your main workplace pension right now. This is the total value, not what you've personally paid in. | Check your pension provider's website or app, or look at your most recent annual statement. If you can't find it, your payslip sometimes mentions your provider. |
| Your monthly contribution | The amount that comes out of your salary each month and goes into this pension. | Check your payslip. It's usually listed as "pension" or "employee pension contribution." A typical auto-enrolment amount is 5% of salary. |
| Employer monthly contribution | The amount your employer adds to your pension each month on top of yours. | Also on your payslip or pension statement. The legal minimum is 3% of qualifying earnings, but many employers pay more. |
| Field | What it means | Guidance |
|---|---|---|
| Essentials (monthly) | What you'd need each month for the basics: housing costs, council tax, utilities, food, insurance, transport. | Think about your current bills minus your mortgage (if it'll be paid off). Most people find essentials sit between £1,000 and £2,000 per month. |
| Fun money (monthly) | Everything else: holidays, restaurants, hobbies, gifts, subscriptions, treating the grandchildren. | Be honest with yourself. £300 to £1,000 is a common range. You can always adjust later. |
Enter these in today's prices. Isaac automatically adjusts for inflation in every future year.
That's it for the initial setup. Isaac immediately shows you a summary: your estimated pot at retirement, how long it lasts, and your readiness score. From here, you can explore the tabs to add more detail and improve accuracy.
Don't have exact numbers? That's completely normal. A rough figure is far better than nothing. You can update any field at any time when you find the right number.
Adding your full pension picture
Most people have more than one pension, especially if they've changed jobs. The Pensions tab is where you add them all. Isaac supports three types, and you can add as many of each as you like.
This is the most common type. You and your employer pay into a pot that's invested in funds. The value goes up and down with the market. When you retire, you use the pot to fund your retirement (by drawing from it, buying an annuity, or a mix of both).
| Field | What it means | Guidance |
|---|---|---|
| Pension name | A label so you can tell your pensions apart. "Current employer" or "Old HSBC pension" works fine. | Whatever makes sense to you. |
| Provider (optional) | The company that manages this pension (e.g. Aviva, Scottish Widows, Nest). | Optional. Helps you keep track if you have several. |
| Current pot value | The total value of this pension right now. | Log into your provider's website or check your annual statement. This is the "fund value" or "total pot value." |
| Your monthly contribution | How much you personally pay in each month. | Check your payslip. If this is an old pension you no longer pay into, set this to £0. |
| Employer monthly contribution | How much your employer adds each month. | Also on your payslip or statement. Set to £0 for old pensions. |
| Annual return (%) | The growth rate Isaac uses to project this pot forward. This is the rate of return before inflation is considered. | Nobody knows the future, but 5% is a commonly used long-term assumption for a balanced fund. Lower (3-4%) is more conservative. Higher (6-7%) is more optimistic. If you want to see different outcomes, use the Scenario Spreads feature (covered in section 5). |
| Link contributions to inflation | If turned on, Isaac increases your contribution amounts each year in line with inflation (so they keep pace with rising prices). | Turn this on if your contributions are a percentage of your salary and your salary roughly tracks inflation. Leave it off if you pay a fixed pound amount that won't change. |
If you know your contributions will change in the future, you can model that. For example, maybe you plan to increase your contributions by £100/month from age 50, or stop contributing entirely at age 60. Each change has:
| Field | What it means |
|---|---|
| From age | The age when this change kicks in. |
| Change type | Increase (add to current), Decrease (subtract from current), Set to (replace with a specific amount), or Stop (contributions go to zero). |
| Amount (monthly) | The amount for this change. Not shown if you chose "Stop." |
Also known as "Final Salary" or "Career Average" pensions. These are less common now but still widespread in the public sector and older private schemes. A DB pension promises you a specific annual income for life when you retire. There's no "pot" to manage.
| Field | What it means | Guidance |
|---|---|---|
| Pension name | A label for this pension. | "NHS Pension" or "Teachers' Pension" or similar. |
| Annual pension (today's money) | The yearly amount this pension will pay you, expressed in today's money. | Check your annual benefit statement. Look for "projected pension at Normal Pension Age" or similar. If you've already left the scheme, look for your "deferred pension" amount. |
| Payment start age | The age this pension starts paying you. | This is usually the scheme's "Normal Pension Age." Common values are 60, 65, or 67. Check your statement. |
| Inflation-linked? | Whether the annual amount increases each year to keep up with inflation. | Most public sector DB pensions are inflation-linked. Many private sector ones are partially linked (they increase, but with a cap). Check your scheme rules. |
| Annual increase cap | If inflation-linked, the maximum annual increase. Only shown if you turned inflation-linking on. | Common caps are 2.5% or 5%. "No cap" means the full inflation rate applies. Check your scheme booklet. |
| Revalues before payment? | Whether the pension amount grows while you're still waiting for it to start (the "deferment" period). This matters if you've left the scheme but haven't reached payment age yet. | Most schemes do revalue deferred pensions. If unsure, leaving this on is the safer assumption. |
The government pension that most UK residents qualify for. Isaac pre-fills the current full rate and calculates your entitlement based on your National Insurance (NI) qualifying years.
| Field | What it means | Guidance |
|---|---|---|
| State Pension age | The age the government starts paying your State Pension. | Currently rising to 67 (between 2026 and 2028), and planned to reach 68 after that. Check gov.uk/state-pension-age for your personal date. |
| NI qualifying years | The number of years you've paid (or been credited with) National Insurance contributions. You need 35 years for the full State Pension. | Check at gov.uk/check-state-pension. The site tells you exactly how many qualifying years you have and how many more you can add. |
| Full State Pension (weekly) | The weekly rate for the full new State Pension. Isaac pre-fills the current rate (£241.30 for 2026/27). | You generally don't need to change this unless you know your rate differs (for example, if you contracted out of SERPS/S2P, you may get less). |
Where to find your pension details: Log into your provider's website, check your annual statement, or look at your payslip. For State Pension, visit gov.uk/check-state-pension. If you've lost track of old pensions, the government's free Pension Tracing Service can help (gov.uk/find-pension-contact-details).
How you plan to spend in retirement
How much you spend in retirement is just as important as how much you save. The Lifestyle tab lets you model your spending in detail.
By default, spending is split into two categories. Everything is entered in today's money (Isaac adjusts for inflation automatically).
| Field | What it means | Guidance |
|---|---|---|
| Essential spending (monthly) | The minimum you'd need each month to cover the basics: housing costs, council tax, utilities, food, insurance, transport, prescriptions. | Think about what you absolutely cannot cut. If your mortgage will be paid off by retirement, don't include it. Most people land between £1,000 and £2,000. |
| Discretionary spending (monthly) | Everything on top of essentials: holidays, eating out, hobbies, gym membership, gifts, entertainment. | Be realistic. Many people underestimate this. Think about what you actually spend now on "fun stuff" as a starting point. |
| Reduce discretionary after age | Most people naturally slow down as they get older and spend less on things like travel and going out. This is the age at which you'd expect that to happen. | There's no right answer. Many people find spending drops off noticeably after 75 or 80. |
| Discretionary reduction (%) | By how much your "fun" spending reduces at that age. | 50% is a common assumption (halving your discretionary spend). You might choose 30% for a gentler drop or 70% for a bigger one. |
Rule of thumb: The Pensions and Lifetime Savings Association (PLSA) publishes "Retirement Living Standards" with three levels: Minimum (~£13k/yr single), Moderate (~£23k/yr single), and Comfortable (~£37k/yr single). These can be a useful benchmark if you're unsure.
If you want more control, you can turn on "Use Spending Curve (Advanced)" to define distinct life stages, each with its own spending level. For example:
| Field | What it means |
|---|---|
| Phase name | A label for this stage of retirement, like "Active years" or "Slowing down" or "Later life." |
| From age | When this phase starts. The first phase always starts at your retirement age. |
| Monthly spend | Your total monthly spending during this phase (in today's money). |
Isaac pre-fills three default phases when you turn this on: "Active years" (full spending from retirement), "Slowing down" (70% of discretionary, starting 10 years into retirement), and "Later life" (40% of discretionary, starting 20 years in). You can rename, rearrange, or add as many phases as you like.
Big expenses that happen once, not every month. Switch to the "Big Purchases" tab within Lifestyle to add these.
| Field | What it means | Guidance |
|---|---|---|
| Purchase name | What the expense is for. "New kitchen," "Round-the-world trip," "New car." | Anything you'd call a one-off cost rather than a monthly expense. |
| Amount | How much it will cost, in today's money. | Isaac adjusts for inflation, so use what it would cost today. |
| Age | The age at which you plan to spend this. | Defaults to your retirement age. Change it to whenever you expect the expense. |
A special card for setting aside money for potential care costs in later life. This ring-fences a lump sum in your pot that Isaac treats as reserved, not available for normal spending. You just enter the amount set aside.
The engine room of your projection
The Assumptions tab is where you control the financial assumptions that drive your projection. You don't need to touch any of these to get started (the defaults are sensible UK-based values), but the more accurate you make them, the more useful your results become.
| Field | What it means | Default | Guidance |
|---|---|---|---|
| Inflation rate | How much prices are expected to rise each year, on average. This affects your future spending, State Pension increases, and inflation-linked DB pensions. | 2.5% | The Bank of England's target is 2%. Long-term UK inflation has averaged around 2-3%. The default of 2.5% sits in the middle of historical norms. |
| Post-retirement return | The annual investment return you expect on your pension pot and ISA after you retire. Before retirement, each DC pension uses its own return rate. | 3.5% | Many people move to lower-risk investments after retiring. 3-4% is a common assumption. If you're staying in growth funds, 5% might be more realistic. This is a nominal return (before adjusting for inflation). |
| Contribution growth rate | The annual rate at which your fixed (non-inflation-linked) DC contributions grow. This models salary-linked increases for contributions that aren't explicitly tied to inflation. | 2.5% | If your contributions are a fixed pound amount and you don't expect them to change, set this to 0%. If they grow with your salary, 2-3% is reasonable. |
If you've already retired, Isaac has two toggles in this section:
| Field | What it means |
|---|---|
| Already drawing State Pension? | If you're already receiving your State Pension, turn this on. Isaac starts it from your current age instead of waiting until State Pension age. |
| Already purchased an annuity? | If you've already bought an annuity, turn this on and enter the annual income it pays. Isaac includes this as guaranteed income from your current age. |
Nobody knows what investment returns will actually be. Scenario spreads let you see a range of outcomes alongside your base case projection.
| Field | What it means | Default |
|---|---|---|
| Optimistic spread (pre-retirement) | How much higher than your base case you'd like the optimistic projection to assume, during working years. If your base case return is 5% and the spread is 1%, the optimistic projection uses 6%. | 1% |
| Optimistic spread (post-retirement) | Same idea, but for after retirement. | 1% |
| Pessimistic spread (pre-retirement) | How much lower than your base case the pessimistic projection assumes. If base is 5% and spread is 1%, pessimistic uses 4%. | 1% |
| Pessimistic spread (post-retirement) | Same idea, but for after retirement. | 1% |
The spreads show up as additional lines on your pot projection chart, so you can see how your plan holds up in both good and bad markets.
If you own property and might use some of that value in retirement (through downsizing or selling), add it here. You can add multiple properties.
| Field | What it means | Guidance |
|---|---|---|
| Property name | A label. "Main home" or "Buy-to-let." | Whatever helps you identify it. |
| Current value | What the property is worth today. | Check recent sale prices for similar properties in your area, or get an online valuation estimate. |
| Growth rate (%) | How much you expect the value to increase each year. | Default is 3%. UK house prices have historically grown around 3-4% per year on average, but this varies hugely by location and period. |
| Plan to sell/downsize? | Whether you plan to release equity from this property. | Turn on if you plan to sell or downsize in retirement. |
| Sell/downsize at age | When you plan to do it. | The age you'd realistically move. |
| Downsize to smaller property? | If you're moving to somewhere cheaper (not selling outright), turn this on. | The equity released is the difference between your current property value (at that future date) and the new one. |
| New property value | What the smaller property would cost in today's money. | Isaac adjusts for growth. The "profit" goes into your retirement pot. |
Property changes are also reflected in your inheritance tax estate. If you sell outright, the property is removed from your estate after the sell age. If you downsize, your estate shows the downsized property value (grown from the sell age) instead of the original.
| Field | What it means | Guidance |
|---|---|---|
| ISA balance | The total current value of all your ISAs (Cash ISA, Stocks & Shares ISA, etc.). | ISA withdrawals are tax-free, which makes them very valuable in retirement. Log into your ISA provider to check your balance. |
| Annual ISA contribution | How much you add to your ISA each year while still working. | The annual ISA allowance is currently £20,000. Enter what you actually put in, not the maximum. |
| ISA expected return (%) | The annual growth rate for your ISA investments. | Similar to pension returns: 4-6% for a stocks & shares ISA, 2-4% for cash ISA. Use what's realistic for your ISA type. |
| Other investments | The value of investments outside ISAs and pensions. General Investment Accounts (GIAs), premium bonds, investment trusts, etc. | These may be subject to capital gains tax when sold. Enter the current value. |
| Cash savings | Money in savings accounts (not ISAs). | Plain cash. Interest on this is typically low. |
Any income in retirement that isn't from pensions, ISAs, or savings. You can add as many sources as you like.
| Field | What it means |
|---|---|
| Income name | What this income is. "Part-time consulting" or "Rental income" or "My Etsy shop." |
| Annual amount | How much it pays per year, in today's money. |
| From age / To age | When this income starts and stops. For example, you might do part-time work from 65 to 70. |
| Grows with inflation? | Whether this income keeps up with rising prices over time. Turn on for things like rental income (rents tend to rise). Leave off for fixed amounts. |
| Owner (Self / Partner) | If you're planning as a couple, who receives this income? This matters for tax calculations. |
If you're expecting to receive a lump sum at some point (an inheritance, a maturing policy, a trust distribution), add it here.
| Field | What it means |
|---|---|
| Name | A description. "Mum's estate" or "Endowment policy." |
| Amount | How much you expect to receive, in today's money. |
| Add to | Where the money goes: Cash (liquid savings, the default), Pension Pot (added to your DC pot, grows with investment returns, taxed on withdrawal), or ISA (tax-free growth and withdrawals). |
| Expected at age | Roughly when you expect to receive it. This is obviously uncertain, so just use your best guess. |
If you're planning as a couple, turn on "Include Partner" and Isaac models your household together: combining incomes, tracking both pots independently, and splitting tax efficiently.
| Field | What it means |
|---|---|
| Partner's date of birth | Isaac calculates your partner's current age automatically from their date of birth. |
| Partner's retirement age | When your partner plans to stop working. |
| Partner's State Pension age | When your partner's State Pension starts. Check gov.uk for their specific date. |
| Partner's NI qualifying years | Their National Insurance qualifying years (default 35). Check gov.uk/check-state-pension. |
| Partner's full State Pension (weekly) | Their weekly State Pension rate. Pre-filled with the current full rate. |
Once partner mode is enabled, you can add pensions and extra income owned by your partner. Each pension and income source has an "Owner" toggle (You / Partner) so Isaac knows who it belongs to for tax purposes.
How you access your pension money in retirement
When you retire, you need to decide how to turn your DC pension pot into income. This is one of the most important decisions in retirement planning, and Isaac lets you model the main options.
You're normally allowed to take 25% of your DC pension pot as a tax-free lump sum, up to a lifetime maximum of £268,275. Isaac offers three methods for how you take it:
| Method | How it works | When to consider it |
|---|---|---|
| Upfront (PCLS) | Take the full tax-free amount as a lump sum when you retire. The rest of your pot is then fully taxable when you withdraw it. | If you need a large cash sum at retirement (to pay off a mortgage, for example) or want to invest it separately. |
| Gradual (UFPLS) | Every time you take money from your pension, 25% of that withdrawal is tax-free and 75% is taxable. No big lump sum up front. | If you want to spread the tax benefit over many years. Can be more tax-efficient if you're withdrawing modest amounts each year. |
| Hybrid | Take some tax-free cash upfront, then use the gradual method for the rest of your tax-free allowance. | If you want some cash up front but don't need the full 25%. |
| Field | What it means |
|---|---|
| Tax-free lump sum percent | What percentage of your pot to take as tax-free cash. Shown for the Upfront and Hybrid methods. Maximum is 25%, and the total is capped at £268,275 per person. |
MPAA warning: Once you start taking taxable money from a DC pension using flexible drawdown, your annual allowance for future contributions drops to £10,000 (the Money Purchase Annual Allowance). Isaac flags this when it applies. This doesn't affect you if you only take the tax-free lump sum.
How you actually draw income from your DC pot after taking any tax-free cash:
| Strategy | How it works | Key consideration |
|---|---|---|
| Flexible Drawdown | Your pot stays invested. You withdraw what you need each year. The remaining pot continues to grow (or shrink, depending on markets). | Maximum flexibility. But the pot can run out if you take too much or markets perform badly. |
| Annuity | You use your pot (or part of it) to buy a guaranteed income for life from an insurance company. Once purchased, the income never stops, but you give up access to the capital. | Security and certainty. You'll never run out of money. But you lose flexibility and access to the pot. |
| Blend | Buy an annuity with part of your pot and draw flexibly from the rest. Best of both worlds for many people. | The blend percentage slider controls what fraction goes to the annuity. |
| Field | What it means | Guidance |
|---|---|---|
| Annuity rate | The percentage of the pot used that gets paid as annual income. For example, if you buy an annuity with £100,000 and the rate is 5%, you get £5,000 per year for life. | Rates depend on your age at purchase and market conditions. As of 2025, rates for a 65-year-old are typically around 5-7%. Check current rates at a comparison site if you want to be precise. |
| Purchase age | The age at which you buy the annuity. It doesn't have to be the same age you retire. | Many people delay their annuity purchase to their 70s, when rates are higher (because the insurance company expects to pay out for fewer years). |
| Annuity escalation (%) | Whether your annuity income increases each year. A 0% escalation means it stays flat (meaning inflation gradually erodes its real value). A 3% escalation means it rises 3% every year. | Escalating annuities cost more (so the starting income is lower), but they protect against inflation. A 0% escalation is the simplest to model. If you want inflation protection, set this to match your inflation assumption. |
| Blend percentage | If using the Blend strategy, what percentage of your pot goes towards buying the annuity. The rest stays in drawdown. | There's no "right" answer. A common approach is 40-60% to annuity (for a secure base income) and the rest in drawdown (for flexibility and growth). |
| Source pension selection | If you have more than one DC pension, you can choose which ones fund the annuity purchase. Isaac calculates the proportion based on how much each pot is projected to be worth at your chosen purchase age. | By default, all DC pensions contribute. You might choose specific pots if, for example, one pension has better drawdown flexibility and you want to keep it for that purpose. |
| Field | What it means | Guidance |
|---|---|---|
| Enable emergency fund | Turn this on to ring-fence a cash buffer that Isaac won't touch during normal drawdown. | A good idea if you want peace of mind. The emergency fund is maintained in your ISA/savings. |
| Reserve amount | The minimum balance to keep in your ISA/savings at all times. Once the balance hits this level, Isaac switches to drawing from your DC pension pots instead. | £5,000 to £15,000 is a common range. Think about what you'd want available for unexpected costs (boiler replacement, car repair, etc.). |
How Isaac calculates your income tax
Isaac calculates UK income tax on your retirement income. This matters because a significant chunk of pension income is taxable, and understanding the tax impact helps you plan more accurately.
| Field | What it means | Guidance |
|---|---|---|
| Include tax in calculations? | Whether Isaac deducts income tax from your pension withdrawals and other taxable income. If turned off, Isaac shows gross (pre-tax) figures. | Leave this on for a realistic picture. The difference between gross and net income can be substantial. |
| Tax region | England, Wales & NI, or Scotland. Scotland has different income tax bands and rates. | Choose where you live (or expect to live in retirement). If you're not sure, pick where you are now. |
| Tax band growth | How income tax thresholds change over time. This has a surprisingly big impact on long-term projections. | Three options:
Frozen (0%) means tax bands stay at today's levels forever. This is the most conservative option, because as your income grows with inflation, more of it falls into higher tax bands ("fiscal drag"). In reality, the UK government has frozen many bands until 2031. Partially frozen (50%) means bands grow at half the rate of inflation. A middle ground. Rise with inflation (100%) means bands keep pace with prices, so there's no fiscal drag. This is the most optimistic option. |
What Isaac handles automatically: Personal allowance (£12,570), basic/higher/additional rate bands, the £100k-£125,140 personal allowance taper, and Scottish starter/intermediate/higher bands. You don't need to enter any of these.
Understanding what your results mean
The Dashboard brings all your inputs together into a visual summary. Here's what each element shows and what it means for you.
At the top of the dashboard, you'll see a colour-coded label that tells you at a glance how your plan looks. This is based on the age at which your money runs out:
| Label | Colour | What it means |
|---|---|---|
| Excellent | Green | Your money lasts beyond age 100. You have more than enough. |
| Very Strong | Green | Money lasts to 96-100. Very solid. |
| Comfortable | Light green | Money lasts to 91-95. Looking good, with a small margin. |
| Moderate | Mint | Money lasts to 86-90. On track, but worth looking for ways to improve. |
| Borderline | Yellow | Money lasts to 81-85. Tight. Consider adjustments. |
| At Risk | Orange | Money lasts to 75-80. You'll likely face a shortfall in later life. |
| Shortfall | Red | Money runs out before 75. Significant changes needed. |
Don't panic about your score. The whole point of Isaac is to let you experiment. If your score is red or orange, try the "What If" suggestions (section 9) to see what changes would make the biggest difference.
| Metric | What it shows |
|---|---|
| Pot at Retirement | Your total estimated wealth at the moment you retire. This includes all DC pension pots, ISAs, other investments, and cash. It's the total amount available to fund your retirement (before any property equity or DB pensions, which are separate). |
| Monthly Spend | What you'll have available to spend each month in retirement, after tax. This is the "take-home" equivalent. |
| Money Runs Out | The age at which your pot hits zero. If it says "100+", your money is projected to last beyond age 100. If it shows an age, that's when you'd run out under the current assumptions. |
| Total Retirement Wealth Today | A snapshot of everything you have right now: current DC pot values, ISA balance, other investments, cash savings, and estimated home equity. This is your starting point. |
The main chart. It shows your total wealth from today until age 100. During your working years, the line goes up (your pots are growing through contributions and investment returns). After retirement, the line curves down (you're spending more than you're earning). If the line reaches zero, that's when the money runs out.
If you've enabled scenario spreads, you'll see additional lines for the optimistic and pessimistic cases, giving you a range rather than a single prediction.
A stacked bar chart showing where your income comes from each year of retirement. The bars are colour-coded by source: State Pension, DB pension income, DC pension withdrawals, ISA withdrawals, extra income, and so on. This helps you understand the mix of income sources and how they change over time (for example, State Pension kicking in at 67, or extra income stopping at 70).
Compares your total income each year against your target spending. When income is above spending, you're in surplus. When spending exceeds income, the gap is being funded from your pot. This chart makes it very clear which years might be tight and where the pressure points are.
Both the Income Breakdown and Income vs Spending charts only appear once you have retirement-age data in your projection. If your retirement age is in the future, you'll need at least one year of post-retirement data for these to show.
A card below the main chart that answers the question "What's the earliest I could retire?" Isaac runs a calculation across different retirement ages and shows you three results:
| Level | What it means |
|---|---|
| Comfortable | The earliest age at which your money lasts to 85. |
| Secure | The earliest age at which your money lasts to 95. |
| Indefinite | The earliest age at which your money lasts to 100+. |
You can tap any of these ages to instantly set your retirement age to that value and see the full projection update.
If your drawdown strategy includes an annuity purchase, this card shows the details:
| Detail | What it shows |
|---|---|
| Purchase cost | The total amount taken from your pot to buy the annuity. |
| Annual income | The guaranteed yearly income the annuity provides. |
| Purchase age | When the annuity is bought. |
| Source pensions | Which of your DC pension pots are used to fund the purchase (if you selected specific sources in the drawdown settings). |
Tap the "Year-by-Year" button in the dashboard header to see a detailed table showing every year from now to 100, with columns for age, pot value, contributions, withdrawals, income by source, tax paid, and remaining balance. This is the most granular view and is also included in the PDF export.
Testing "What If?"
This is where Isaac becomes genuinely powerful. Instead of looking at one fixed plan, you can create multiple versions and compare them.
A scenario is a complete set of inputs: your age, pensions, spending, assumptions, everything. Your first scenario is created automatically during onboarding. From there, you can:
Long-press a scenario card to duplicate it. Then change one thing (retire 2 years later, save £100 more per month, spend £200 less) and see exactly what difference it makes.
Swipe between scenario cards on the dashboard. Each card shows the key metrics (retirement age, when the money runs out, monthly spend, contributions) so you can compare at a glance.
Tap the scenario name at the top of the dashboard to open the scenario switcher, which lists all your scenarios with their key stats.
Isaac includes a dedicated What If tool that lets you tweak any assumption and instantly compare the impact side by side. You can adjust things like:
You can freely explore and edit assumptions on the What If screen. Viewing the side-by-side comparison charts is a Premium feature. If you like the result, you can save it as a new scenario with one tap.
The question isn't "What will happen?" (nobody can know that). The question is "What could happen, and which version do I want to aim for?" Scenarios help you answer that.
Going deeper when you're ready
You don't need any of these to use Isaac. But once you've set up the basics and you want a more detailed picture, these features let you get there.
Model retirement as a couple. Isaac tracks both partners' pensions independently, combines household income, applies tax to each person separately, and shows the combined picture. You can also link accounts with your partner for shared scenario access.
Generate a branded A4 report with your projection charts, income breakdowns, and year-by-year tables. Useful for sharing with a financial adviser, discussing with your partner, or keeping for your own records. The report includes all the same data you see on the dashboard, laid out for printing.
See optimistic and pessimistic projections alongside your base case. If markets do better or worse than you assumed, how does your plan hold up? The spread lines on the pot chart show the range of possible outcomes.
Define different spending levels for different stages of retirement. Most people spend more in their 60s and 70s (travel, activities) and less in their 80s and 90s. Spending phases let you model this realistically.
Add your home value and model what happens if you downsize or sell. The released equity feeds into your retirement pot at the age you specify.
Set aside a minimum cash buffer that Isaac won't touch during normal drawdown. If your ISA/savings balance drops to this level, Isaac switches to drawing from your pension pots instead, keeping the cash reserve intact for emergencies.
See an estimate of your estate's IHT liability at any age. Add gifts (Potentially Exempt Transfers) with 7-year taper relief, IHT shields (AIM shares with Business Relief, agricultural and business property relief), and life insurance policies. Use the age slider to see how your estate and tax liability change over time.
Download all your scenario data as a formatted spreadsheet with Summary, Pensions, Assets & Liabilities, Year-by-Year projection, and IHT Planning sheets. Useful for deep analysis or sharing raw data with an adviser.
If you create an account (free), your scenarios sync across all your devices. Isaac also works offline. Changes made offline are queued and synced automatically when you reconnect.
If you received an organisation code from your employer or adviser, you can enter it during sign-up or later in your Account settings. Organisation codes link your account to an employer or corporate programme.
Plain English explanations for pension and financial terms
Practical advice from real use
Enter your main pension and spending first. Look at the results. Then gradually add ISAs, property, extra income, and partner details. Each addition makes the picture more accurate, but even the basics give you a useful starting point.
Don't try to model one "perfect" plan. Duplicate your scenario and try different retirement ages, contribution levels, or spending amounts. The value is in understanding the range of possibilities and which levers make the biggest difference.
When you get your annual pension statement, update your pot values. Even small changes compound over decades, so keeping things current gives you the best picture. Set a calendar reminder if it helps.
Enable scenario spreads and look at the pessimistic line on your pot chart. If your plan still works when markets underperform, you can feel genuinely confident. If it doesn't, that's useful information too.
Every input in Isaac has a small information icon next to it. Tap it for an explanation of what that field means, why it matters, and what a typical value looks like. If you're ever unsure about a field, start there.
If you're working with a financial adviser, the PDF export gives them a detailed snapshot of your projections. It's a great conversation starter and saves time explaining your situation from scratch.
The point isn't to predict the future exactly. It's to understand the shape of your retirement finances. Are you roughly on track? Where are the risks? What changes would help the most? That's what matters. A rough projection that you actually use is worth far more than a perfect one you never make.
The fact that you're planning at all puts you ahead of most people. Research consistently shows that people who engage with their pension projections make better financial decisions. Even a basic projection is better than no projection.
Managing your account and personal information
Isaac stores your pension scenarios, preferences, and basic account information so you can access your plans across devices. We never sell your data to third parties. For full details on what we collect and how we use it, see our Privacy Policy.
You can permanently delete your Isaac account at any time. Here's how:
Tap the Account tab at the bottom of the app, then scroll down to find the account management options.
At the bottom of the Account screen, tap the Delete Account button (shown in red).
You'll be asked to confirm. Once confirmed, your account and all associated data will be permanently deleted. This action cannot be undone.
What gets deleted: Your user profile, all saved scenarios, and preferences are permanently removed. If you have an active Premium subscription, you should cancel it through your device's app store (Apple App Store or Google Play Store) before deleting your account to avoid continued billing.
When you delete your account, Isaac performs the following:
This process is irreversible. If you'd like to use Isaac again in the future, you'll need to create a new account and re-enter your information.
If you're having trouble deleting your account or have questions about your data, contact us at support@isaacmoney.com and we'll assist you.
Isaac is a financial planning tool designed to help you explore and understand your retirement finances. It is not financial advice, and nothing in this app or guide should be treated as a recommendation to buy, sell, or hold any financial product.
All projections are estimates based on the assumptions you enter. Future investment returns, inflation, tax rates, and government policy are all uncertain and will differ from any projection. Past performance is not a guide to future performance.
Isaac does not know your full financial circumstances, goals, or risk tolerance. Before making any financial decisions, you should consult a qualified, FCA-regulated financial adviser who can give you personalised advice based on your individual situation.
Isaac is not regulated by the Financial Conduct Authority (FCA) and does not provide regulated financial advice.