How to calculate compound interest
- Type the starting amount, the yearly rate and the time.
- Choose how often interest is compounded, and add a monthly deposit if you have one.
- Read the final amount and the yearly table.
About this tool
Compound interest earns interest on the interest you have already made. Enter a starting amount, the yearly rate and the time, then choose how often it compounds. You can also add a regular monthly deposit, as in a recurring deposit or a monthly saving plan. A year-by-year table shows how much you paid in and how much came from interest.
Common questions
What is the compound interest formula?
A = P x (1 + r/n) ^ (n x t), where r is the yearly rate as a decimal, n is the compounds per year and t is the years.
How are monthly deposits handled?
Each month the balance earns the monthly equivalent of your rate, then the deposit is added. You can choose whether deposits go in at the start or the end of the month.
Will my bank show exactly this number?
It can differ slightly, because banks have their own day counts and rounding. Use this for planning and the bank's schedule for the final figure.
Is it free to use?
Yes. There's no sign-up, and you can use it as often as you like.
Is my text uploaded anywhere?
No. This tool runs inside your browser, so what you enter stays on your device.
Do I need to install anything?
No. It works in your browser on a computer or a phone.