# Compound interest calculator UK | ComputeNow

URL: https://computenow.co.uk/compound-interest-calculator/

> See how a lump sum and monthly additions grow with compound interest, compounded yearly, quarterly, monthly or daily.

This calculator shows a worked example below. To use your own figures, add them to the URL as query parameters (listed in https://computenow.co.uk/llms.txt), for example https://computenow.co.uk/compound-interest-calculator/?<parameter>=<value>.

[What's Left, step 5 of 7: How much should I put aside?](https://computenow.co.uk/money-plan/#steps)

# Compound interest calculator

See how a lump sum grows when interest is earned on interest.
Rates checked 18 October 2026
By the ComputeNow team, checked against GOV.UK and HMRC[Sources (1)](#sources)[How we calculate](https://computenow.co.uk/methodology/)

After 10 years you will have
£16,288.95
including £6,288.95 of interest.

Your £16,288.95

- Starting amount £10,000.00 (61%)
- Interest £6,288.95 (39%)

## 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.

### Next steps

- [Savings calculator](https://computenow.co.uk/savings-calculator/?start=10000&monthly=0&rate=5&years=custom&yearsCustom=10)Add tax on interest and a year-by-year table.
[What's Left](https://computenow.co.uk/money-plan/) adds up your monthly figures from each calculator and shows what is left each month.
[After 10 years you will have £16,288.95 Breakdown](#result)

## 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.

## Related calculators

[Savings calculator How your savings grow with interest](https://computenow.co.uk/savings-calculator/)[Savings goal calculator How much to save each month](https://computenow.co.uk/savings-goal-calculator/)[Investment and ISA calculator How investments could grow](https://computenow.co.uk/investment-calculator/)

## Guides and help

### Our guides

[UK interest rates and inflation today Average mortgage, savings, loan and card rates](https://computenow.co.uk/guides/uk-interest-rates-and-inflation/)[How big could your pension be? Pension pots by the age you start saving](https://computenow.co.uk/guides/pension-pots-by-age/)

### Official services and free advice

[Individual Savings Accounts (ISAs) GOV.UK: tax-free saving and investing](https://www.gov.uk/individual-savings-accounts)[Tax on savings interest GOV.UK: the Personal Savings Allowance](https://www.gov.uk/apply-tax-free-interest-on-savings)[Check your money is protected FSCS: cover if a bank or provider fails](https://www.fscs.org.uk/)

## Sources

Each source was last checked on 18 October 2026.

- [GOV.UK: Individual Savings Accounts](https://www.gov.uk/individual-savings-accounts)
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.