Retirement Calculator

What the retirement calculator does

The Retirement Calculator projects the size of your defined-contribution pension pot at your chosen retirement age and translates it into an estimated retirement income. It is built for anyone paying into a workplace scheme, a personal pension or a SIPP who wants a quick, transparent view of where their current savings and monthly contributions are heading — including internationally mobile professionals and expats weighing up how much they still need to set aside. Rather than a black box, it uses a straightforward compound-growth model you can reproduce by hand, so you can see exactly how each input moves the result. It sits alongside our other retirement and planning tools and the UK Pensions hub, and is intended as the starting point for a conversation rather than a substitute for a full cashflow plan.

How the projection works

You enter seven figures: your current age, target retirement age, current pension savings, monthly contribution (including anything your employer pays in), an expected annual return, an inflation rate and a drawdown rate. The calculator works out the number of years to retirement, then grows your pot month by month. Each month it applies one-twelfth of your annual return to the running balance and then adds your monthly contribution — the standard compounding you would get from reinvested growth. Over 25 years that is 300 compounding steps, which is why a small change to the return assumption has an outsized effect on the final figure.

Two versions of the pot are shown. The headline number is the nominal pot — the actual pounds you would expect to see on a future statement. Beneath it, the calculator shows the pot in today's money, deflating the nominal figure by your inflation rate across the whole period so you can judge its real spending power. To turn the pot into income it applies your drawdown rate to the nominal pot — a 4% rate implies you draw 4% of the pot in the first year — and displays this as both an annual and a monthly income. It also splits the final pot into how much came from your own contributions versus investment growth, which is often the most motivating number on the page.

The assumptions and limitations

Because the model is deliberately simple, it makes several assumptions worth keeping in mind. It assumes a single, constant rate of return every month — real markets rise and fall, and the order of good and bad years matters enormously once you start withdrawing, a problem known as sequencing risk. It assumes your monthly contribution stays flat in cash terms, so in real terms your paying-in power quietly erodes with inflation unless you increase it over time. It does not deduct product or fund charges, which compound against you just as growth compounds for you. And it does not model tax — neither the tax relief that boosts contributions on the way in, the 25% tax-free lump sum, nor the income tax due on drawdown. The drawdown figure is a flat percentage of the starting pot; it does not simulate the pot depleting or continuing to grow through retirement.

Critically, the projection excludes the State Pension. If you have a qualifying National Insurance record, that is a valuable, inflation-linked income on top of your private pot — estimate it with the State Pension Calculator and add it to the drawdown income shown here for a fuller picture.

How to read your result — a worked example

Take the tool's default scenario: a 40-year-old with £50,000 already saved, paying in £500 a month, assuming 6% growth and 2.5% inflation, retiring at 65. The calculator projects a pot of roughly £570,000 in nominal terms — but only about £307,000 in today's money, a gap that shows how much inflation erodes over 25 years. Of that £570,000, only £200,000 is money you actually paid in; the remaining ~£370,000 is investment growth, the reward for starting early and staying invested. At a 4% drawdown rate the pot would generate around £22,800 a year, or roughly £1,900 a month, before any State Pension. Nudge the return to 5%, push the contribution to £600, or retire two years later and watch how the ending pot responds — that sensitivity is the real lesson of the tool, far more than any single headline number.

Why it matters and what to do next

A projection turns a vague worry — "am I saving enough?" — into a figure you can act on. If the income looks short of what you'll need, you have levers: contribute more, work a little longer, review your investment strategy, or plan a lower-cost retirement. Compare the drawdown income against a realistic target with the Pension Gap Calculator, sense-check how long a pot can support withdrawals using our guide to the sustainable withdrawal rate, and if you are deciding between a guaranteed income and flexible access, read annuity versus drawdown. For expats and cross-border savers, where and how you draw income also carries tax consequences in more than one country, so the headline pot is only part of the picture — and the point at which personalised advice earns its keep.