What this pension calculator does
A defined contribution pension – the type most private-sector workers now have through automatic enrolment – builds up a pot of money invested on your behalf. What that pot is worth when you retire depends on four things: how much goes in, how long it is invested, how the investments perform and how much is lost to charges. This calculator projects your pot year by year using assumptions you choose, then expresses the result in today's money so you can compare it with your current cost of living.
Projections are illustrations, not promises. Investment returns are not guaranteed and can be negative in any given year. Use the results to see the shape of the outcome and the effect of changing your contributions, rather than as a precise forecast.
The inputs explained
- Current age and retirement age – the gap is your investment horizon. Under current rules the earliest age you can usually access a private pension (the normal minimum pension age) is 55, rising to 57 from 6 April 2028.
- Current pot – the combined value of the pensions you want to include. If you have several old workplace pensions, you can find lost ones with the free government Pension Tracing Service.
- Monthly contribution – enter the total going in each month, including your contribution, your employer's contribution and tax relief. Under auto-enrolment the minimum total is 8% of qualifying earnings, with at least 3% from the employer (source: GOV.UK workplace pensions).
- Annual growth – an assumed average investment return before charges. Lower, more cautious figures give a more conservative picture.
- Annual charges – fund and platform fees, expressed as a percentage. Default workplace schemes are subject to a charge cap of 0.75% a year, and many charge less.
- Inflation – used to convert the final pot into today's money.
Why charges and time matter so much
Growth compounds: returns earn returns. That makes time the most powerful factor in pension saving – money contributed in your twenties typically has far more time to grow than money contributed in your fifties. The same compounding works in reverse for charges. A difference of half a percentage point a year can look trivial, but over a 35-year working life it can reduce a final pot noticeably. Try changing the charges input by 0.5% and watch the result move.
Tax relief: the government's top-up
Pension contributions generally receive tax relief at your marginal rate, subject to the annual allowance (normally £60,000 a year, or 100% of your earnings if lower). In practice, a basic-rate taxpayer contributing £80 from net pay into a relief-at-source scheme has £100 invested; higher and additional-rate taxpayers can claim extra relief through Self Assessment or their tax code. With salary sacrifice, you also save National Insurance. These reliefs make pensions one of the most tax-efficient ways to save for retirement.
Taking money out
From minimum pension age you can usually take up to 25% of your pot tax-free, subject to the Lump Sum Allowance of £268,275 for most people. The rest is taxed as income when you withdraw it. Common options are:
- Drawdown – keep the pot invested and withdraw flexibly.
- Annuity – exchange some or all of the pot for a guaranteed income for life or a set period.
- Lump sums – take cash in chunks, each partly tax-free and partly taxable.
The free, government-backed Pension Wise service offers impartial guidance on these options if you are 50 or over.
Don't forget the State Pension
Your private pension is likely to sit alongside the State Pension. The full new State Pension is £241.30 a week for 2026/27 (source: GOV.UK), which is about £12,548 a year, and you normally need 35 qualifying years of National Insurance to receive it in full. Check your own forecast on GOV.UK and use our State Pension Age Calculator to see when it starts.
How much is enough?
There is no single right number. A practical approach is to estimate the annual income you would need in retirement – housing costs, bills, food, transport, leisure, help with the home – subtract your expected State Pension, and see how large a pot you would need to provide the rest. Independent organisations such as the Pensions and Lifetime Savings Association publish Retirement Living Standards that describe minimum, moderate and comfortable lifestyles, which can be a useful reference point.
This is an illustration only and is not financial advice. Pension rules can change. Consider regulated financial advice before making major pension decisions.