Compound Interest Calculator
Instantly calculate total principal and interest, plus yearly progression, from principal, annual rate, and period
Features
Instant calculation from principal and annual rate
Total amount and earnings update automatically as you change inputs
Supports monthly contributions
Estimate future assets for systematic investment plans
Choose from 3 compounding frequencies
Switch between annual, semi-annual, or monthly interest accrual
View year-by-year progression table
See total amount and cumulative invested amount for each year
How to Use
Enter principal, annual rate, and period
Input principal amount, annual interest rate (%), and investment period (years)
Set contributions and frequency if needed
Enter monthly contribution amount and choose compounding frequency: annual, semi-annual, or monthly
View results and progression table
No execute button needed—total amount, total invested, earnings, and year-by-year progression display instantly
Use Cases
Estimate interest on savings
Determine how much your deposit will grow based on interest rate and time period
Project future investment assets
See how much you'll accumulate with regular monthly contributions
Find conditions to reach your goal
Compare required rates, periods, and contributions to reach your target amount
Estimate debt growth
See how much compound interest will increase a loan before borrowing
Knowledge Base
Difference between compound and simple interest
Compound interest reinvests earnings into the principal for the next calculation, while simple interest only applies to the original principal. At 5% annual rate over 10 years, simple interest yields 1.5× the principal, but compound interest (annually) yields about 1.63×.
- Compound interest：Compound interest reinvests received interest into the principal before calculating the next period's interest, with larger growth over longer periods.
- Simple interest：Simple interest does not reinvest received interest. Interest is always calculated on the original principal only.
Rule of 72
Divide 72 by the annual interest rate (%) to find approximately how many years it takes for your investment to double. At 3% annual rate, 72÷3 ≈ 24 years; at 6%, 72÷6 ≈ 12 years.
Why compounding frequency affects results
With the same annual rate, more frequent interest accrual means more opportunities for interest to compound. At 5% over 10 years, the total is about 1.629× the principal annually, 1.639× semi-annually, and 1.647× monthly.
Safety and Privacy
Runs entirely in your browser
Your input data is processed only within your browser and is never sent externally.
Processing only in your browser
Calculation is processed entirely within your browser, and input data is not sent to any server.
Communications encrypted with HTTPS
Page loading is also encrypted by TLS, and content cannot be read by third parties.
No transmission to third parties
Input content is not sent to external services such as ad networks or trackers.
No automatic saving of results
Entered amounts and interest rates and input suggestions are not stored on the server.
Updates
- update #246
Compound Interest Calculator added: displays total principal and interest plus year-by-year progression from principal and annual rate