Compound Interest Calculator
See how savings grow with compound interest and monthly deposits.
Your answer
Turn on JavaScript to use this calculator. The formula is explained below so you can work it out by hand.
How this calculator works
Compound interest earns interest on your interest. The calculator converts the annual rate and compounding frequency into an equivalent monthly rate, then grows the balance month by month and adds your deposit at the end of each month.
Monthly rate = (1 + annual rate ÷ n)n ÷ 12 − 1, where n is compounding periods per year
Each month: balance = balance × (1 + monthly rate) + deposit
Example
Start with $1,000, add $100 a month, and earn 5% compounded monthly. After 10 years you've put in $13,000 and the balance is about $17,175, so roughly $4,175 came from interest.
Category: Personal Finance