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Savings Calculator

Work out how much a regular savings habit could be worth. Enter a starting balance, a monthly amount and an interest rate to estimate your future balance and the interest earned.

Inputs

Estimate how regular monthly saving and interest could grow your balance.

How the savings estimate works

The calculator applies the interest rate to your balance each month, then adds your monthly saving. Because interest is earned on a growing balance, the longer you save the larger the share of your final balance that comes from interest rather than deposits.

AER and how rates are quoted

UK savings accounts usually quote an Annual Equivalent Rate (AER), which reflects how interest builds up over a year. Using the AER gives a fair comparison between accounts that pay interest monthly, annually or at maturity.

Tax on savings interest

Most basic-rate taxpayers can earn £1,000 of savings interest a year tax free through the Personal Savings Allowance, falling to £500 for higher-rate taxpayers. Interest inside a Cash ISA is tax free and does not use this allowance.

Worked examples

Building an emergency fund

Starting with £1,000 and saving £150 a month at 4% for five years, most of the final balance comes from your own deposits, with interest adding a steady top-up.

Saving for a deposit

Increasing the monthly amount or the time period has a much larger effect on the final balance than small differences in the interest rate.

How we calculate this

Interest is estimated monthly using one twelfth of the annual rate entered, then the monthly saving is added.

Deposits and interest are tracked separately so the result shows how much of the balance you saved and how much is interest.

The estimate does not deduct tax or adjust for inflation, and assumes the rate stays the same for the whole period.

Official sources

FAQs

Is the interest rate guaranteed?

Only if you hold a fixed-rate account for its full term. Easy-access and variable rates can change at any time, which would change the result.

Does this include tax on interest?

No. The estimate is before tax. Interest above your Personal Savings Allowance may be taxable, while interest in a Cash ISA is tax free.

What rate should I use?

Use the AER quoted by the account you are considering. If you are unsure, comparing a range of rates shows how sensitive the result is.

Should I save or invest?

Saving suits money you may need soon or cannot risk. Investing may suit longer-term goals where you can accept the value rising and falling.

Money

Save vs Invest

Compare saving and investing for risk, access, inflation and long-term growth.

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Read the full comparison

Saving protects capital and works best for short-term goals. Investing offers higher long-term growth potential but comes with volatility and loss risk. Most people need both: cash for emergencies and near-term plans, investments for longer-term wealth building.

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