“Am I saving enough?” is the retirement question everyone asks and few can answer, because the answer depends on growth, time, and what you will actually spend. This calculator turns a vague worry into a number: your projected pot at retirement, and the annual income it might support, for savers in both the UK and the US.
Retirement Savings Calculator
Project your pension pot at retirement and the income it could provide under the 4% rule.
Year-by-year projection
| Age | Contributions so far | Growth so far | Pot value |
|---|
How it works: your pot grows monthly at the return you enter (annual rate divided by 12), with your contribution added each month, until your chosen retirement age. The 4% rule is a common rule of thumb suggesting you could withdraw 4% of the pot in your first year of retirement and adjust for inflation after that — it’s a guide, not a guarantee. This projection ignores inflation, fees, tax and any state pension (UK) or Social Security (US) income, and real returns will vary.
How it works
Enter your current age, target retirement age, current pension or retirement savings, and your monthly contribution — including any employer contribution, since employer money is part of your real saving rate. Add an expected annual growth rate, and optionally the annual income you are aiming for.
The calculator projects your pot at retirement, estimates the income it could provide, and shows the gap if you fall short, along with the extra monthly saving that would close it. Run it once with your current contribution and once with a small increase: the difference a modest rise makes over 25 years is usually the most motivating number on the page.
How the calculation works
Your existing pot is projected forward with compound growth: it is multiplied by (1 + growth rate) for each year until retirement. Your monthly contributions are accumulated the same way, each payment compounding for the time remaining. The default growth assumption of 5% a year represents a typical diversified pension portfolio after charges and roughly in line with long-term inflation-adjusted planning assumptions — deliberately more conservative than headline stock market averages.
To convert a pot into income, this calculator uses the widely used 4% rule of thumb: withdrawing 4% of the pot in the first year of retirement, then adjusting for inflation, has historically lasted around 30 years for a balanced portfolio. In the UK, the result should be read alongside the State Pension (a full new State Pension is worth roughly £12,000 a year) and the option to take up to 25% of a pension pot tax-free, usually capped. In the US, it sits alongside Social Security, which replaces a larger share of income for lower earners. Annuity purchase, drawdown and cash are different ways of turning the same pot into income, with different risks.
Worked example: age 35, £50,000 saved, £400 a month, retiring at 67
Step 1 — Project the existing pot. 32 years of growth at 5%: £50,000 × (1.05)³² = £50,000 × 4.764 ≈ £238,200.
Step 2 — Project the contributions. £400 a month (£4,800 a year) for 32 years at 5% grows to roughly £361,400, even though the contributions themselves total only £153,600.
Step 3 — Total pot. £238,200 + £361,400 ≈ £600,000 at age 67.
Step 4 — Income it supports. At 4%, £600,000 provides about £24,000 a year, before adding the State Pension. With a full State Pension of roughly £12,000, total income approaches £36,000 a year — which is why a £600,000 pot goes further than it first appears. Miss five years at the start, however, and the same plan ends nearer £455,000.
Things to watch
- Employer contributions are free money — capture all of them. In the UK, auto-enrolment minimums total 8% of qualifying earnings, but many employers will match more if you contribute more. In the US, contribute at least enough to get the full 401(k) match; declining a match is declining part of your pay.
- Fees quietly shrink your pot. A pension charging 1% a year more than a competitor can leave you with a pot roughly 20% smaller over a full career. Old pensions from previous jobs often charge far more than modern workplace schemes.
- Do not forget the tax-free element. UK savers can normally take 25% of their pot tax-free from age 55 (rising to 57 in 2028). US Roth accounts flip the model: contributions are taxed now, withdrawals in retirement are tax-free. The calculator shows pre-tax pots, so your spending power depends on how you withdraw.
- Inflation decides what the number means. £600,000 in 32 years is not £600,000 in today’s money. At 2.5% inflation it buys roughly what £272,000 buys today. Judge your target income in today’s terms, and remember state benefits are generally inflation-linked while a level annuity is not.
- Retirement age is your most powerful lever. Retiring at 62 instead of 67 in the example above cuts the pot by well over £100,000 and adds five more years of spending. Even part-time work for a few years changes the maths dramatically.
Frequently asked questions
How much do I need to retire comfortably in the UK?
The Pensions and Lifetime Savings Association estimates a “moderate” retirement for a single person costs around £31,000 a year and a “comfortable” one around £43,000, including the State Pension. Subtract your expected State Pension and multiply the remaining annual income need by about 25 to get a rough target pot.
What is a realistic savings rate?
A common rule of thumb is to save half your age as a percentage of income when you start: start at 30 and save 15% (including employer contributions), start at 40 and aim nearer 20%.
Should I use 4% as my withdrawal rate?
It is a planning benchmark, not a guarantee. It was derived from US historical data over 30-year retirements. Retiring very early, expecting high fees, or wanting certainty pushes planners towards 3–3.5%; flexible spending in retirement can support more.
How do UK and US retirement saving differ?
The growth mechanics are identical, but the wrappers differ: UK pensions get tax relief on the way in and are taxed on withdrawal beyond the 25% tax-free portion, while the US combines pre-tax 401(k)s and IRAs with Roth accounts taxed in reverse.
Is it too late to start at 50?
No, but the maths changes: with 17 years to 67, contributing £400 a month from scratch would build roughly £124,000 — still a meaningful supplement to the State Pension, especially with employer matching and tax relief.
This calculator is for guidance only and isn’t financial advice.