Retirement Calculator
Estimate your retirement pot from your current savings and monthly contributions, and the income it could provide.
Content updated July 1, 2026
Simplified nominal projection — excludes inflation, tax, and state/workplace pensions.
Retirement can feel abstract until you see the numbers. This calculator projects how large your retirement pot could grow between now and the age you plan to stop working, based on what you've already saved and what you add each month.
It then applies a sustainable withdrawal rate to estimate the annual income that pot might provide — a useful reality check on whether you're on track, or need to save more or work a little longer.
The Retirement formula
Pot = P × (1 + r)ⁿ + C × [ ((1 + r)ⁿ − 1) ÷ r ]; Income ≈ Pot × wPot = projected fund at retirement · P = current savings · C = monthly contribution · r = monthly return (annual return ÷ 12, as a decimal) · n = months until retirement · w = annual withdrawal rate (e.g. 0.04 for the 4% rule).
Worked example
With $50,000 saved, adding $500 a month for 25 years at 6% a year: r = 0.06/12 = 0.005 and n = 300. The lump sum grows to about $223,000 and the contributions to about $346,000, for a pot near $569,000 — roughly $22,800 a year at a 4% withdrawal rate.
How the projection works
Your current savings and monthly contributions are grown at your assumed annual return up to your retirement age, using monthly compounding. The result is your projected pot in nominal terms.
To estimate income, the calculator applies a withdrawal rate you choose. The often-cited '4% rule' suggests withdrawing about 4% of the pot in the first year and adjusting for inflation after — a rough guide, not a guarantee, and one that assumes a diversified portfolio and a typical retirement length.
Important caveats
This is a simplified projection. It doesn't model inflation eroding your income, taxes, state or workplace pensions, or the sequence of market returns — all of which matter in real life.
Treat it as a directional tool: it's excellent for seeing whether saving more, retiring later, or earning a slightly higher return meaningfully changes your outcome. For a formal plan, speak to a qualified financial adviser.
Frequently asked questions
▶How much do I need to retire?
A common rough rule is 25× your desired annual spending (the inverse of a 4% withdrawal rate). This calculator estimates the pot you're on track to build and the income it could support so you can compare against your target.
▶What is the 4% rule?
It's a guideline suggesting you can withdraw about 4% of your retirement pot in year one, then adjust for inflation, with a reasonable chance the money lasts ~30 years. It's a starting point, not a promise.
▶How is my retirement pot projected?
Your current savings are compounded to retirement age, and each monthly contribution is grown using the future-value-of-an-annuity formula. The two are added to give the projected pot, which is then multiplied by your withdrawal rate to estimate annual income.
▶How much should I be saving for retirement?
There's no single figure, but many guides suggest putting aside around 15% of income, including any employer contributions. The right amount depends on your target income, your age, and how much you've already built up — try a few contribution levels above.
▶When should I start saving for retirement?
As early as you can. Because contributions compound for decades, money invested in your twenties does far more work than the same amount invested later. Starting sooner is the single biggest advantage most people have.
▶Does this include the state pension or inflation?
No. The projection is a simplified nominal figure and doesn't model the state or workplace pension, tax, or inflation eroding your income. Treat it as a directional guide and use lower assumptions to be cautious.
Learn more
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Open calculator →Disclaimer: Retirement Calculator results are estimates for general information and education only, and are not financial, tax, legal or medical advice. Verify important decisions with a qualified professional.