Savings interest calculator
£10,000 saved at 4% AER grows to about £12,167 after 5 years, earning £2,167 in interest.
- You pay in
- £17,000
- Interest earned
- £2,319
£5,000 to start, plus £200 a month, at 4% AER for 5 years. Before any tax on the interest.
Assumes the rate stays the same and you take nothing out. Before any tax on the interest.
What you pay in and what interest adds
What £10,000 grows to
One-off £10,000, nothing else paid in, interest left to build up.
| AER | 1 year | 3 years | 5 years | 10 years |
|---|---|---|---|---|
| 2% | £10,200 | £10,612 | £11,041 | £12,190 |
| 3% | £10,300 | £10,927 | £11,593 | £13,439 |
| 4% | £10,400 | £11,249 | £12,167 | £14,802 |
| 5% | £10,500 | £11,576 | £12,763 | £16,289 |
Saving £200 a month
Starting from nothing, paying in £200 at the end of each month.
| AER | 1 year | 3 years | 5 years | 10 years |
|---|---|---|---|---|
| 2% | £2,422 | £7,412 | £12,604 | £26,519 |
| 3% | £2,433 | £7,520 | £12,916 | £27,890 |
| 4% | £2,444 | £7,628 | £13,236 | £29,339 |
| 5% | £2,455 | £7,738 | £13,563 | £30,873 |
How we calculate this
AER (annual equivalent rate) shows what you would earn in a year with interest added and left in the account. We turn the AER into the matching monthly rate and add interest each month, so interest also earns interest.
Monthly payments are added at the end of each month. Real accounts may add interest monthly or yearly, but quoting the AER makes the yearly result the same either way.
Questions people ask
What is the difference between AER and gross rate?
The gross rate is the interest rate before tax. AER shows what you would earn over a year if interest is added and left in, so it lets you compare accounts that pay interest monthly with ones that pay yearly.
What is compound interest?
It is interest earned on your interest. Each time interest is added, the next lot is worked out on the bigger balance, so savings grow faster the longer you leave them.
Do I pay tax on savings interest?
Many people don’t, because of the Personal Savings Allowance and tax-free accounts like ISAs. If your interest goes over your allowance, it is taxed. GOV.UK explains how much you can earn tax-free.
Will my rate stay the same?
Only on fixed-rate accounts. Easy access rates can go up or down at any time, so treat the result as a guide.
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