Compound interest calculator (principal, rate, periods)
Enter a principal, the interest rate for each period and the number of periods. The balance, the total interest and a table for every period appear as you type.
Runs in your browser. Nothing you type is uploaded.
How it works
Balance = principal × (1 + r)ⁿ, where r is the interest rate per period and n the number of periods.
Example: a fixed deposit of 100,000 at 2% a year for 3 years grows to 100,000 × 1.02³ = 106,120.80. A loan of 100,000 at 1% a month with nothing repaid grows to 112,682.50 after 12 months.
The formula
Balance = principal × (1 + r)ⁿ, where r is the rate per period and n the number of periods. With an amount added every period, each addition earns interest from the period it is added.
Use a rate that matches the period: a yearly rate with years, a monthly rate with months. 2% a year is not the same as 2% a month.
Examples
A fixed deposit of 100,000 at 2% a year for 3 years: 100,000 × 1.02³ = 106,120.80, of which 6,120.80 is interest.
A loan of 100,000 at 1% a month with nothing repaid: after 12 months, 100,000 × 1.01¹² = 112,682.50 is owed.
Questions
What is compound interest?
Interest that is added to the balance and then earns interest itself in the following periods.
How is it different from simple interest?
Simple interest is worked out on the principal only. Compound interest is worked out on the principal plus the interest already added, so the balance grows a little more each period.
Why is the rate field empty?
The calculator does not assume any rate. Enter the rate that applies to your deposit, loan or account.
Can I use a monthly rate?
Yes. Enter the monthly rate and the number of months: the rate and the periods must use the same unit of time.
For calculation only. Not financial advice.