Compound Interest Tools

Compound Interest Calculator

Compound Interest Calculator

Estimate future value, regular deposits or withdrawals, inflation, tax and fees. Share the result, download a table, or copy an Excel formula.

Inputs

Your calculation

£
%

£
£
%

% annually
%
%

Outputs

Results

Enter your numbers and click calculate.

Final balance
£0.00
Total contributions
£0.00
Withdrawals: £0.00
Interest earned
£0.00
Tax/fees: £0.00

Year-by-year table

A yearly summary of balance, contributions and interest.

YearDepositsWithdrawalsInterestTax / feesEnd balance

What if I start 5 years earlier?

Calculate to see the comparison.

Simple vs compound interest

Calculate to see the comparison.

Excel formula

Copy a formula based on your current inputs.

=FV(...)

Growth chart

Visualise how your balance builds from the starting amount plus accrued interest.

Yearly chart

Month-by-month table

Click a year to expand the monthly breakdown.

Guide

How to use this compound interest calculator

Enter your starting amount, annual interest rate and time period, then choose how often the interest is compounded. You can also add regular deposits or withdrawals, inflation, tax and annual fees.

The results include a final balance, total contributions, interest earned, a yearly table, a month-by-month breakdown and a growth chart. Use the share URL to save the calculation or send it to someone else.

Compound interest formula

The standard formula is A = P(1 + r/n)nt, where P is the starting amount, r is the annual rate, n is the number of compounding periods per year, and t is the number of years.

For regular deposits, the calculator works month by month so that different contribution frequencies, timing, inflation and fees can be handled more clearly.

FAQ

Compound interest calculator FAQ

Compound interest means interest is added to the balance, then future interest is calculated on the larger balance. Over time this can make growth faster than simple interest.

Yes. The calculator supports weekly, monthly and annual contributions, with deposits made at the beginning or end of the contribution period.

Yes. After calculating, use the Copy share URL button. The page stores the inputs in the query string so the same calculation can be opened again.

Yes. You can download the monthly breakdown as CSV or Excel and copy an Excel formula based on the current inputs.