Compound Interest Calculator
The compound interest calculator computes the final amount using A = P*(1 + r/n)^(n*t), where P is principal, r is annual rate, n is compounding frequency per year, and t is years. Unlike simple interest, compound interest earns interest on accumulated interest, resulting in exponential growth. This calculator shows the year-by-year balance growth in a table below. Select the compounding frequency (annually, semi-annually, quarterly, monthly, or daily).
Formula
A = P * (1 + r/n)^(n*t)
Interest = A - P
where r is the decimal form of the rate
Year-by-year growth
Compound interest calculator: frequently asked questions
What is compound interest?
Compound interest is interest earned on both the principal and accumulated interest. The formula is A = P*(1 + r/n)^(n*t), where P is principal, r is annual rate, n is compounding frequency per year, and t is years.
What is the difference between daily and monthly compounding?
Daily compounding calculates interest 365 times per year. Monthly compounding calculates 12 times per year. More frequent compounding results in slightly higher final amounts.
Which compounding frequency is best?
For savers, daily compounding is best (more interest earned). For borrowers, annual compounding is best (less interest paid). Most savings accounts use daily compounding.
What if compounding is continuous?
For continuous compounding, use the formula A = P*e^(r*t). See the continuous compound interest calculator for this.
How much difference does compounding frequency make?
For short periods or low rates, the difference is small. For long periods or high rates, more frequent compounding can make a significant difference.
Official sources
- Wikipedia: Compound Interest.
- Wolfram MathWorld: Compound Interest.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.