What's Left, step 5 of 7: How much should I put aside?
Compound interest calculator
See how a lump sum grows when interest is earned on interest.
After 10 years you will have
£16,288.95
including £6,288.95 of interest.
Where it comes from
| Item | Total |
|---|---|
| Starting amount | £10,000.00 |
| Interest earned | £6,288.95 |
| Final balance | £16,288.95 |
This is an estimate, not financial advice.
How compound interest works
Each year's interest is added to the balance, so the next year earns interest on a bigger amount: £10,000 becomes £10,500, then £11,025, and so on.
The rule of 72 is a quick check: divide 72 by the rate to see roughly how many years it takes to double. At 5% that is about 14 years.
Common questions
How much will £10,000 grow in 10 years at 5%?
With interest compounded once a year it grows to £16,288.95, so £6,288.95 of interest. Compounded monthly it reaches £16,470.09.
What is compound interest?
Interest earned on your interest as well as on what you put in. Each year the interest is added to the balance, so the next year’s interest is worked out on a bigger amount.
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These results are an estimate, not financial advice. They use the 2026/27 rates in force on 24 October 2026 and the inputs shown, so your actual tax, pay or costs may differ. Before making a decision about your money, check the figures with HMRC or your provider, or speak to a regulated financial adviser. Free, impartial guidance is available from MoneyHelper.
This page explains the rules using the 2026/27 rates in force on 24 October 2026. It is general information, not financial advice. For decisions about your own money, speak to a regulated financial adviser, or get free, impartial guidance from MoneyHelper.