Pension Calculator UK: Project Your Retirement Pot

Project your pension pot with the calculator above

Enter your age, current pension value, monthly contribution, employer contribution and the age you plan to stop working. The tool above compounds your savings year by year and returns an estimated pot at retirement. Change the growth rate or the amount you pay in and the projection updates instantly, so you can test what a small increase today does to the number decades from now.

How the pension calculator works

A pension is just an investment pot with generous tax treatment. Three forces drive how big it gets: how much goes in, the tax relief added on top, and how long it compounds. The calculator models all three. The core formula for each year is simple:

End-of-year pot = (start pot + yearly contributions) × (1 + growth rate)

That result becomes the start pot for the next year, and the cycle repeats until your chosen retirement age. Because each year's growth is earned on top of the previous year's growth, the pot curves upward rather than rising in a straight line. This is compounding, and over a 30 or 40-year working life it does most of the heavy lifting.

Contributions come from three places. You pay in from your salary; your employer adds their share; and HMRC adds pension tax relief at your highest rate of income tax. A basic-rate taxpayer gets 20% relief, so an £80 net contribution becomes £100 in the pot. A higher-rate taxpayer can reclaim a further 20% through Self Assessment, and an additional-rate taxpayer a further 25%. In Scotland the relief follows the Scottish income tax rates, so the exact top-up differs from the rest of the UK, but the principle is identical: the taxman effectively pays part of your contribution.

The growth rate is the one number nobody can promise. It reflects how your fund is invested, the charges deducted and how markets behave. A common planning approach is to model a real or nominal return and then stress-test it lower. The calculator lets you set this yourself rather than baking in a fixed figure, because the right assumption depends on your fund choice and how many years you have left.

Worked example: a 35-year-old nurse building a pot

Priya is 35, earns £35,000 and has £20,000 in her NHS-style workplace pension. She pays in £200 a month and her employer adds £150 a month. With basic-rate tax relief, her own £200 is topped up so the gross amount entering the pot is higher than the cash leaving her bank account.

Say total gross contributions land at roughly £4,800 a year once relief and the employer share are counted. Assume 5% annual growth and a retirement age of 67, giving 32 years of compounding. Year one looks like this:

• Start pot: £20,000
• Add contributions: £20,000 + £4,800 = £24,800
• Apply 5% growth: £24,800 × 1.05 = £26,040

Repeat that loop for 32 years and the pot grows into six figures, with the majority of the final value coming from growth rather than the cash she paid in. The lesson is blunt: the contributions matter, but the years matter more. Someone who starts the same plan at 45 instead of 35 ends up with a markedly smaller pot, because they lose ten of the most powerful compounding years.

Worked example: the cost of waiting five years

Take two savers, both aiming to retire at 67 with £300 a month going in and 5% growth. Sam starts at 30. Alex starts at 35. Alex pays in for five fewer years, but the real damage is the lost compounding on the early money. By retirement Sam's pot is tens of thousands of pounds larger, despite paying in only £18,000 more in cash. That gap is pure compound growth on contributions made early. If you can only do one thing after reading this, start sooner rather than paying in more later.

How to get a bigger pot without feeling much poorer

There are a handful of levers that move the projection more than people expect:

• Capture the full employer match. Many schemes increase their contribution if you increase yours. Not claiming the maximum match is leaving free money on the table.
• Use salary sacrifice where offered. Swapping salary for a pension contribution can cut your National Insurance as well as income tax. Our salary sacrifice calculator shows the take-home impact.
• Reclaim higher-rate relief. If you pay 40% or 45% tax, the extra relief above the basic 20% is not always automatic in a personal pension. You may need to claim it through Self Assessment.
• Mind the charges. A 1% annual fee instead of 0.3% can quietly remove a large slice of the final pot over decades. Compare the fund charges in your scheme.
• Keep contributing for longer. Even delaying retirement by two years adds contributions and lets the whole pot compound further.

If you want to see how the projected pot might convert into a retirement income, pair this tool with our pension drawdown calculator and annuity calculator, which model what the pot pays out rather than how it builds up.

Annual Allowance and other limits to watch

There is a ceiling on how much you can pay into pensions each year with tax relief. The pension Annual Allowance is £60,000 for 2026/27, covering your contributions, your employer's and the relief together. High earners can have this tapered down, and anyone who has already started drawing flexibly may face a lower money purchase limit. If you are paying in large sums or have several pots, check the position with our pension annual allowance calculator before assuming everything qualifies for relief. The official rules sit on the gov.uk pension allowance pages.

Most pensions also let you take 25% of the pot tax-free from age 55 (rising to 57 from 2028), with the rest taxed as income when you draw it. That tax-free element is a major reason pensions beat ordinary savings for retirement, alongside the relief on the way in. For a tax-free wrapper without the access restrictions, some savers also use an ISA; the annual ISA allowance is £20,000.

Common mistakes people make with pension projections

• Assuming an unrealistic growth rate. Plugging in 8% or 10% makes the number look great but sets you up for disappointment. Model something cautious and treat anything higher as a bonus.
• Forgetting inflation. A pot of £400,000 in 35 years will not buy what £400,000 buys today. Think in terms of what the income will actually cover.
• Ignoring the State Pension. Your private pension sits on top of the State Pension. Check your entitlement with a State Pension forecast so you are not double-counting or under-counting.
• Counting only your own contributions. Leaving out the employer share and tax relief understates the pot badly. The calculator includes all three for a reason.
• Losing track of old pots. If you have changed jobs, you may have several dormant pensions. Find them before you project, or your real total is higher than you think.

For the bigger retirement picture, including when you can afford to stop, try our broader retirement calculator alongside this one.

If you want to understand exactly how the relief part is calculated, the MoneyHelper pensions guidance is a clear, independent reference backed by the government.

These projections are estimates for guidance only and are not personal tax or financial advice. Investment returns are not guaranteed and the value of a pension can fall as well as rise.

Related pension and retirement calculators

Carry on planning with our pension pot calculator, work out the tax saved on contributions with the pension tax relief calculator, or model a self-invested pot with the SIPP calculator.

The numbers: pension limits and what relief is worth

Official guidance: GOV.UK pension tax and free advice from MoneyHelper.