Interest Calculator

Calculate simple and compound interest with year-by-year breakdowns and APY comparison.

Mode

Principal

Annual Interest Rate

Time

What is an Interest Calculator?

Calculate simple and compound interest on savings or investments. Compare growth over time with year-by-year breakdown.

How to Use

Using the interest calculator is very simple:

Enter your values in the input fields
Click the calculate button
View the results instantly

Tips

Double-check your inputs for accurate results
This tool is for estimation - consult a professional for important decisions
Save your results for future reference

Frequently Asked Questions

What is the difference between simple and compound interest?+

Simple interest is calculated only on the original principal: I = P * r * t. Compound interest is calculated on the principal plus accumulated interest, so you earn 'interest on interest'. Over time, compounding grows faster.

What is APY?+

APY (Annual Percentage Yield) is the effective annual rate when compounding is considered. A 5% rate compounded monthly has an APY of 5.12%. APY lets you compare accounts with different compounding frequencies.

How often should interest be compounded?+

More frequent compounding earns slightly more. $10,000 at 5% for 10 years: monthly compounding = $16,470, annual compounding = $16,289 - a difference of $181. Daily compounding adds even less on top of monthly.