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Compound interest calculator (UK)

See what a balance grows to with regular deposits, any compounding frequency, and inflation in today’s money.

Compound interest calculator

The quoted annual rate.

How often interest is added to the balance.

Leave blank for a lump sum only.

Contributions are made

Paying in at the start earns one extra period of interest each time.

Enter a rate to also see the result in today’s money.

Balance after 10 years

£38,075

£9,075 of that is interest.

You put in
£29,000
Interest earned
£9,075
Effective annual rate
4.594%

After compounding.

Interest as a share
24%

Of the final balance.

Year-by-year breakdown (10 years)
Balance, contributions and interest for each year
YearOpeningPaid inInterestClosing
1£5,000£2,400£280£7,680
2£7,680£2,400£403£10,483
3£10,483£2,400£532£13,414
4£13,414£2,400£666£16,481
5£16,481£2,400£807£19,688
6£19,688£2,400£955£23,043
7£23,043£2,400£1,109£26,551
8£26,551£2,400£1,270£30,221
9£30,221£2,400£1,438£34,060
10£34,060£2,400£1,615£38,075

Interest rates are assumed fixed and tax is not deducted. Real savings rates move, and what is taxable depends on your country and account type.

Estimate only. This result is produced from the figures you entered and the assumptions listed on this page. It is not financial advice, not a quotation and not an offer, and no provider is bound by it. Check current terms with the provider before acting. Nothing you type here is sent anywhere — the calculation runs entirely in your browser.

How this is worked out

A = P(1 + r/n)^(nt) + PMT × [((1 + i)^(mt) − 1) ÷ i]

What this assumes

A calculator is only as good as what it leaves out. These are the assumptions built into the result above.

  • The interest rate is fixed for the whole period. Real savings rates move.
  • Deposits are made at the end of each period unless you switch to the start.
  • Tax on interest is not deducted. What is taxable depends on your country and account type.
  • Inflation, when entered, discounts the final figure into today’s money.

Educational information only. This page explains how something works in the United Kingdom. It is not financial advice and does not take account of your circumstances. Rates, fees and eligibility change without notice — check the provider’s own terms before you act.

For free, impartial guidance, see MoneyHelper. To complain about a firm, contact the Financial Ombudsman Service.

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