Free Compound Interest Calculator
Enter a principal, annual rate, compounding frequency and time period to watch your money grow. The calculator shows the future value, total interest earned, effective annual rate and a year-by-year breakdown table.
How to Use the Compound Interest Calculator
- Enter the principal, annual interest rate and time period.
- Choose how often interest compounds.
- Click Calculate Growth for the future value and yearly table.
Features
Supports yearly, half-yearly, quarterly, monthly and daily compounding with the exact A = P(1+r/n)ˣᵗ formula. The yearly table reveals how growth accelerates as interest starts earning its own interest.
Benefits & Use Cases
Compare savings accounts, fixed deposits and bonds on equal footing, or demonstrate to students why starting early beats investing more later. The effective-rate readout exposes the true yield behind advertised rates.
Tips
Nominal rates mislead — always compare the effective annual rate the tool shows. Small rate differences compound into huge gaps over decades, so even 1% matters.
Frequently Asked Questions
What is compound interest?
Interest calculated on both the original principal and previously earned interest, so growth accelerates over time.
How often should interest compound?
More frequent compounding grows money slightly faster; the calculator lets you compare yearly through daily to see the difference.
What is the effective annual rate?
The true yearly yield after accounting for compounding frequency — the fairest way to compare two advertised rates.
Simple vs compound interest?
Simple interest pays only on the principal; compound interest pays on principal plus accumulated interest, growing much faster over long periods.
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