Savings Calculator
Use this savings calculator to see how a starting balance and monthly deposits could grow, how much interest you could earn and, if you want, an estimate of tax on that interest.
Checked 20 October 2026.
Deposit timing
Your band depends on your total income including interest. Interest in a cash ISA is not taxed, so leave this off for ISA savings.
Final balance
£19,319.07
This is an estimate. Your provider's figures may differ. Interest in a cash ISA is not taxed.
- Starting balance
- £5,000.00
- Total deposits
- £12,000.00
- Total interest earned
- £2,319.07
- Term
- 60 months
Year by year
| Period | Deposits | Interest | Balance at end |
|---|---|---|---|
| 1 | £2,400.00 | £243.69 | £7,643.69 |
| 2 | £2,400.00 | £349.44 | £10,393.12 |
| 3 | £2,400.00 | £459.41 | £13,252.54 |
| 4 | £2,400.00 | £573.79 | £16,226.33 |
| 5 | £2,400.00 | £692.74 | £19,319.07 |
Show the working
- Monthly rate used: 0.003274. This is (1 + AER) to the power of 1/12, minus 1.
- Each month the balance earns interest at the monthly rate, then the deposit is added.
- Final balance = starting balance + deposits + interest = £5,000.00 + £12,000.00 + £2,319.07 = £19,319.07.
Nothing you enter leaves your device. This is not financial or tax advice. Interest rates and tax rules can change. Check your account terms and GOV.UK before you decide.
How is savings interest worked out?
With compound interest you earn interest on your original amount and on the interest already added, so the longer you save the more you benefit (MoneyHelper). This savings interest calculator treats your rate as an AER and works out interest monthly using (1 + AER)^(1/12) - 1.
MoneyHelper's example of £1,000 at 2% reaching £1,104 after five years gives £1,104.08 here, which shows compound interest on savings at work.
Savings growth examples
| AER | 1 year | 5 years | 10 years |
|---|---|---|---|
| 3% | £10,300.00 | £11,592.74 | £13,439.16 |
| 4% | £10,400.00 | £12,166.53 | £14,802.44 |
| 5% | £10,500.00 | £12,762.82 | £16,288.95 |
Illustrative rates only, not offers. Before tax. Interest worked out monthly.
| Monthly saving | 1 year | 5 years | 10 years |
|---|---|---|---|
| £100 | £1,221.84 | £6,617.90 | £14,669.59 |
| £250 | £3,054.61 | £16,544.76 | £36,673.98 |
| £500 | £6,109.22 | £33,089.51 | £73,347.96 |
Illustrative rates only, not offers. Before tax. Interest worked out monthly.
How much savings interest is tax free?
GOV.UK sets the Personal Savings Allowance at £1,000 for basic rate taxpayers, £500 for higher rate taxpayers and £0 for additional rate taxpayers.
There is also a starting rate for savings of up to £5,000 of interest if your other taxable income, not counting savings interest or dividends, is under £17,570. It falls by £1 for every £1 of other income above your Personal Allowance. Your tax band is based on total income including interest. GOV.UK says you can save tax-free with Individual Savings Accounts: see the ISA allowance calculator.
Will tax on savings interest change?
Yes. GOV.UK says the rates of income tax on savings income rise by 2 percentage points across all bands from April 2027.
The 2026/27 tax rates this savings tax calculator uses are 20%, 40% and 45% (GOV.UK income tax rates), and the "from April 2027" option adds 2 points to each. GOV.UK notes that income tax bands are different in Scotland, so check GOV.UK if you live there.
Is it better to save or pay off debt?
MoneyHelper says to pay off more expensive debts before thinking about reducing your mortgage, and that saving might make more sense if you can find a better rate of return than the rate you are being charged.
Compare your savings rate with the rate on your borrowing. The mortgage overpayment calculator and the loan calculator show what that borrowing costs.
Common questions
How much will £10,000 grow in a savings account?
At 4% AER with no further deposits, £10,000 grows to £10,400.00 after 1 year, £12,166.53 after 5 years and £14,802.44 after 10 years, before tax. Examples only, not offers.
How much will I have if I save £250 a month?
At 4% AER with deposits at the end of each month and nothing to start, £250 a month grows to £3,054.61 after 1 year, £16,544.76 after 5 years and £36,673.98 after 10 years, before tax.
Does this calculator include tax by default?
No. Switch on the tax estimate to see tax above your Personal Savings Allowance. It ignores the starting rate for savings, so it can overstate tax if you have little other income.
Why is my account balance different from the result?
Rates can change, and providers credit interest on different dates. MoneyHelper notes that savings interest could differ if the rate of interest changes. Use your provider's figures for the exact balance.
Should I use AER or the gross rate?
Enter the AER, because this calculator works out interest monthly from the effective yearly rate. If your account shows only a gross rate, check your provider's AER figure.
Sources
Checked 20 October 2026:
This is not financial or tax advice. Interest rates and tax rules can change. Check your account terms and GOV.UK before you decide.
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