Pension Pot Calculator: See How Big Your Retirement Fund Could Grow

Project your pot in seconds

Enter your details in the tool above to get an instant projection. Start with your current balance (check your latest pension statement), add your regular monthly contribution including anything your employer pays, set how many years until you plan to retire, and pick a growth rate. The pension pot calculator then estimates what your fund could be worth on the day you stop work.

How the projection is worked out

Two things are happening at once: the money already in your pot keeps growing, and every new contribution starts growing too. The calculator adds both together.

The maths behind it is compound growth. Your existing pot follows this formula:

Future pot = Current pot × (1 + growth rate)^years

Your stream of monthly contributions is treated as a regular investment that compounds over time:

Future value of contributions = Yearly contribution × [ ((1 + growth rate)^years − 1) ÷ growth rate ]

Add the two results together and you have the projected pot. Because each year's growth earns growth of its own, the curve gets steeper the longer you leave it — which is why starting early matters far more than paying in large amounts late. If you want to see the pure effect of that snowball on any lump sum, our compound interest calculator breaks it down year by year.

One important point: contributions into a UK pension usually attract tax relief, so the amount that actually lands in your pot is bigger than what leaves your bank account. A basic-rate taxpayer paying £240 from take-home pay has it grossed up to £300 in the pension (because £240 ÷ 0.80 = £300). Higher-rate taxpayers can claim more back through their tax return. Our pension tax relief calculator shows exactly how much the government adds for your salary.

Worked example: Sarah, age 35

Sarah has £30,000 in her workplace pension. Between her own pay and her employer's contribution, £400 a month (£4,800 a year) goes in. She plans to retire at 67, so she has 32 years to go, and she assumes 5% average annual growth after charges.

• Existing pot grows to: £30,000 × 1.05³² = £142,948
• Her contributions grow to: £4,800 × [ (1.05³² − 1) ÷ 0.05 ] = £361,434
• Projected pot at 67: £142,948 + £361,434 = £504,382

Sarah pays in £4,800 × 32 = £153,600 of her own money over those years. The other £350,782 is growth. That gap is the whole point of starting in your thirties rather than your fifties.

Worked example: why the growth rate dominates

Keep everything about Sarah the same but assume 3% growth instead of 5%, perhaps because charges are higher or markets are weaker:

• Existing pot: £30,000 × 1.03³² = £77,252
• Contributions: £4,800 × [ (1.03³² − 1) ÷ 0.03 ] = £252,013
• Projected pot: £329,265

The same savings habit produces around £175,000 less. Two percentage points does not sound like much, but over three decades it reshapes your retirement. This is why people pay close attention to annual management charges — a 1% fee is effectively a 1% cut to your growth rate every single year.

How a £400-a-month pot builds over time

Using Sarah's 5% scenario, here is how the pot grows in stages. Notice how the later decades add far more than the early ones, even though the contribution never changes.

Between 55 and 67 the pot more than doubles, despite only £57,600 of fresh contributions going in over those years. That acceleration is compounding doing the heavy lifting.

Ways to grow your pot faster

• Grab the full employer match. Many schemes increase their contribution if you raise yours. Turning down a match is turning down free money on top of tax relief.
• Use salary sacrifice where it is offered. Paying in before tax and National Insurance can stretch the same take-home cost further. Our salary sacrifice calculator shows the effect on your payslip.
• Bump contributions when your pay rises. Diverting part of a pay rise before you get used to spending it barely dents your lifestyle but compounds for decades.
• Mind the annual allowance. Most people can pay in up to £60,000 a year (including employer contributions and tax relief) before extra tax charges apply; it can be tapered for high earners. Check yours with the pension annual allowance calculator.
• Don't forget the State Pension. Your private pot sits on top of it. A State Pension forecast tells you the foundation you are building on.

For the official rules on how pension tax relief works, see GOV.UK pension tax relief, and for free, impartial guidance on retirement planning the government-backed MoneyHelper pensions service is a good starting point.

Common mistakes to avoid

• Picking an unrealistic growth rate. Headline figures of 8% or 9% ignore charges and inflation. A real-terms 3%-5% is a more honest planning range.
• Forgetting inflation. A £500,000 pot in 2058 will not buy what £500,000 buys today. Think about what the figure means in today's money before you celebrate.
• Ignoring old pensions. Job-hoppers often leave small pots behind. Tracing and combining them gives you a truer current balance to start the projection from.
• Assuming the whole pot is spendable. When you draw your pension, you can normally take part of it tax-free and the rest is taxed as income. How you withdraw it affects the tax — our pension drawdown calculator models that stage.
• Stopping during tough months. Pausing contributions for a year early on can cost far more than the year's payments, because you lose decades of growth on that money.

What happens at the regional level

Pension tax relief and the annual allowance are UK-wide, but the income tax you reclaim and the tax you eventually pay on withdrawals depend on where you live. Scotland sets its own income tax rates and bands, so a Scottish higher-rate taxpayer may reclaim relief at a different rate from someone in England, Wales or Northern Ireland. The projection of the pot itself is the same wherever you live; only the tax treatment around it shifts.

These projections are estimates for guidance only and are not personal tax or financial advice. Investment returns are not guaranteed, and you should consider speaking to a regulated adviser before making decisions about your pension.

Who should use this calculator

This is deliberately narrow: what will the pot itself be worth, without modelling income, drawdown or the State Pension. It is the building-phase view, useful for a quick check on whether current contributions are heading anywhere near the target.

The most instructive way to use it is to change one thing at a time. Adding £100 a month, or retiring two years later, or shaving 0.5% off the fee — run each separately and the relative power of the three becomes obvious. For most people mid-career, the fee change is the smallest lever and the extra contribution the largest.

What this calculator assumes

• The pot grows at a steady annual rate, compounded, which is a planning simplification.
• Monthly payments in continue unchanged, with no career break or step up.
• Any fee entered is charged annually on the balance.
• The projection is of the pot only, not the income it might produce.

Limitations — what it does not cover

• What the pot converts into. Turning it into a sustainable income is a separate problem — see the drawdown and annuity calculators.
• Tax on withdrawal beyond the 25% tax-free element.
• The State Pension and other pots held elsewhere.
• Market volatility and sequence risk.
• Contribution limits, including the tapered annual allowance.
• Inflation, unless you deliberately enter a real rather than nominal growth rate.