Savings & compound interest
Explore how a starting balance and monthly deposits could grow.
Your numbers
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Your result
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Enter your numbers and select Calculate to see the breakdown.
An estimate, not a guaranteed return or investment recommendation. Rates can change; fees, tax and inflation are excluded. Enter an AER, not a nominal annual rate.
How it works
Monthly growth factor = (1 + AER ÷ 100)^(1/12). Interest is applied monthly, followed by your deposit at the end of each month. The rate stays constant.
A quick example
£1,000 plus £100 at each month-end for one year at 0% interest gives £2,200. Any growth shown is before tax and inflation.
Good to know
When are deposits added?
At the end of each month, after that month’s interest. Depositing earlier would produce a slightly larger balance.
Does this model investments?
It models smooth interest growth only. Investments can fall in value and do not produce a fixed, guaranteed monthly return.