Interest Calculator
Calculate simple or compound interest on any amount.
Calculator
Simple interest
$150
Compound interest (monthly)
$161.47
Final value (compound)
$1,161.47
What is interest?
This interest calculator computes either simple or compound interest on a principal amount over time at a given annual rate.
Example
$1,000 at 5% simple interest for 3 years earns $150 in interest. The same at 5% compounded monthly earns $161.47.
Money-saving tips
- •Compound interest grows faster than simple interest over time.
- •Compare APR and APY when evaluating savings or loan products.
- •Higher compounding frequency means more interest earned or paid.
Common mistakes
- •Confusing nominal rate with effective rate.
Financial definitions
- Nominal rate
- The stated annual interest rate, not accounting for compounding.
Frequently asked questions
Related calculators
Simple Interest Calculator
Calculate simple interest using the formula I = P × r × t.
Compound Interest Calculator
Calculate how compound interest grows your money over time with optional regular contributions.
APR Calculator
Convert between APR and APY based on compounding frequency.
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Estimate how much you need in an emergency fund based on your monthly expenses and target months of coverage.
Estimated reading time: 4 min