Investment & retirement calculator

See what your money could become. Enter what you have and what you add, and watch compound interest do the work, in pounds, dollars or euros, adjusted for inflation.

Currency
What do you want to work out?
£
yrs
%
£
More options (compounding, inflation)
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Used only to show your balance in today's money.

How it builds up

Money you put in Growth
YearStartPaid inGrowthBalance
Illustration only. This calculator assumes a constant annual return and does not account for fees, taxes or market volatility. It is not personal financial advice. Investments can fall as well as rise and you may get back less than you put in.

How the investment calculator works

Every month, your balance earns a slice of growth based on your return rate, and then any contribution is added. The next month, growth is calculated on the new, larger balance. That is compound interest: returns earning returns. Over decades it does most of the heavy lifting, which is why starting early matters more than starting big.

Use the tabs to solve for whatever you do not know. Pick "Contribution" and set a target, and we work out the monthly amount you need. Pick "Return rate" to see what growth would get you there. Switch to Multiple pots to give cash, ISAs and pensions their own rate, which is closer to how real portfolios behave.

A realistic word on returns

No investment grows in a smooth line. A "7% a year" assumption is a long-run average that hides good years and frightening ones. Keep an emergency buffer in cash, invest for the long term, and revisit your plan rather than your balance. The today's-money figure reminds you that inflation quietly eats into big future numbers.

Investment calculator FAQ

How does compound interest work?

You earn returns on your past returns, not just your original money. Each period your balance grows, and the next period's growth is worked out on the bigger balance, so the effect speeds up the longer you leave it.

What return rate should I use?

It depends where the money sits. People often model cash around 2 to 4 percent, and a diversified stock-market ISA or pension around 5 to 7 percent after costs. These are rough long-run guides, not guarantees. Use the multiple-pots mode to give each one its own rate.

Why show a figure in today's money?

Inflation erodes spending power. £500,000 in 30 years will not buy what £500,000 buys now. The today's-money figure discounts your projected balance by your chosen inflation rate so you can judge what it would really be worth.

Is this investment advice?

No. It is for illustration and education only, it assumes a steady return that real markets never deliver, and it is not personal financial advice. If you are unsure, speak to a regulated financial adviser.

Project your real money, not a hypothetical

EveryPound plugs in your actual ISAs, pensions and savings, projects your net worth to retirement, and lets Addy tell you where the next £100 should go. Free, no bank login.