How does the calculator work out when my money runs out?

It grows your pot each year until you retire, then takes out what you need to cover the gap between your spending and your State Pension and any final salary pension, after income tax. The age the pot reaches zero is the answer. Everything is in today's money.

Yes. It applies 2026/27 UK income tax bands to your pension withdrawals, State Pension and final salary pension, with the first 25% of pension withdrawals tax-free up to the Lump Sum Allowance. Scottish bands are available.

Is this financial advice?

No. It is a calculator for illustration. Its results depend entirely on the figures and growth rate you enter, and it is not a personal recommendation. Isaac is not regulated by the FCA.

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How long will your money last?

Put in what you have, what you pay in and what you plan to spend. Isaac projects it year by year, takes UK income tax off, and tells you the age the money runs out. Everything is in today’s money.

Your money lasts to

–

You retire at

–

Pot at retirement

–

Income before tax, first year retired

–

Tax in first year retired

–

Your pot, year by year

Building upDrawing downState Pension starts

That’s the rough answer. Isaac does the real one.

Build your plan in Isaac and add the things this page can’t: each pension separately, your partner, property, inheritance, the spending curve, and the tax-free cash and drawdown order that change the answer.

Three scenarios: optimistic, base and cautious
“What would it take?” to retire earlier or spend more
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Year by year

Age	Pot at start	State Pension	Final salary	Taken from pot	Tax	Spending	Pot at end

Today’s money throughout: growth is the amount above inflation, and tax bands are frozen in real terms, as the Government has announced to 2031. The first 25% of each pension withdrawal is tax-free up to the Lump Sum Allowance of £268,275; ISA money is tax-free. Your pot is drawn after your guaranteed income and ISAs. It stops at 100.

How this calculator works

Until you retire, your pots grow at the rate you set and your monthly contributions are added each year. From retirement, the calculator works out what you need after tax, takes your State Pension and any final salary pension first, then your ISAs and savings, and finally draws from your pension pot. Each year’s pension withdrawals are taxed with the 2026/27 bands, with 25% of each withdrawal tax-free while your Lump Sum Allowance lasts. The age at which the pot reaches zero is the headline.

What it leaves out

Your partner’s pensions and personal allowance, which can change the tax picture a lot.
Taking tax-free cash up front rather than a bit at a time, and the order you draw from different pots.
Property, inheritance, one-off costs, a spending curve that falls later in life, and a Monte Carlo view of bad luck in the markets.
National Insurance is not charged on pension income, so none is applied.

All of those are in the Isaac app, free to start.

Where the figures come from

The full new State Pension for 2026/27 is £241.30 a week, or £12,548 a year. The personal allowance is £12,570, the basic rate band runs to £50,270 and the higher rate to £125,140; Scotland has its own starter, basic, intermediate, higher, advanced and top rates. The Lump Sum Allowance is £268,275. Isaac’s calculation methodology page explains how the app itself works in more detail.

Isaac is an educational planning tool, not financial, investment, tax or legal advice, and Budgetwise Limited is not authorised or regulated by the Financial Conduct Authority. The result depends entirely on the figures and assumptions you enter; pensions and investments can go down as well as up. For decisions about your own money, consider a qualified, FCA-regulated adviser.