Retirement calculator
What your pot could grow to, and what it would be worth in today's money.
- Runs in your browser — nothing you enter is uploaded
- No sign-up, no quotas, free to use as often as you like
How it works
Two numbers decide a retirement projection: how long the money compounds, and what inflation does to it meanwhile. Most calculators show the first and quietly skip the second, which is how you end up with an impressive-looking figure that does not buy what you think it does.
Compounding, monthly
Growth is applied monthly on the balance and on each contribution from the month it is added. The result separates what you put in from what the growth added, which is the comparison worth seeing — over a long horizon the growth usually dwarfs the contributions, and that is the entire argument for starting early.
Today's money
The projection is also shown adjusted for inflation. A pot of a million in forty years at 2.5% inflation buys roughly what 370,000 buys now. Both figures are real; the second is the one to plan with.
The 4% rule
A rough yearly income is shown based on withdrawing 4% of the pot annually, a common rule of thumb from studies of historical portfolio survival. It is a starting point for a conversation, not a guarantee — it depends on asset mix, fees, taxes, how long retirement lasts and what markets do.
What this cannot model
A steady annual return, which no real market provides. Sequence-of-returns risk — a crash early in retirement hurts far more than the same crash later — is not modelled. Nor are fees, taxes, state pensions, or changes to your contributions. Every one of those matters. Treat this as a shape, not a forecast.
Retirement calculator — questions
What return should I assume?
Historical long-run equity returns before inflation are often quoted between 6% and 8%, but past returns do not promise future ones and fees reduce what you keep. Try a few figures and see how much the answer moves.
Why show an inflation-adjusted figure?
Because a large number decades away buys much less than it appears to. The real-terms figure is the one to plan against.
What is the 4% rule?
A rule of thumb that withdrawing 4% of the pot each year has historically lasted about thirty years. It is a starting point, not a guarantee.
Does it include fees and taxes?
No. Both reduce the outcome, sometimes substantially, so treat the projection as an upper bound.
Is this financial advice?
No. It is a compound growth calculation and should not be treated as a recommendation.