Compound Interest Calculator
Calculate compound interest with configurable compounding frequency.
A compound interest calculator projects how an investment grows when interest is reinvested, with options for how often it compounds.
How to Use the Compound Interest Calculator
- Enter the principal. Type the initial amount.
- Set rate, time, frequency. Enter the annual rate, years, and compounds per year.
- Read the result. See interest earned and the final amount.
This tool processes your input locally in your browser. Nothing is uploaded.
What Is Compound Interest?
Compound interest is how investments and savings grow over time, because interest earns interest on itself.
Formula
Amount = principal × (1 + rate/compounds)^(compounds × years). The more frequently it compounds, the faster it grows.
Why compounding matters
Over long periods, compounding produces exponential growth. Starting early and reinvesting returns dramatically increases the final value.
Key Features
- Configurable compounding
- Interest earned
- Final amount
- Growth %
Examples
- $1,000 at 5% compounded monthly for 10 years grows to about $1,647.
Common Use Cases
- Investments
- Retirement planning
- Long-term savings
Tips & Best Practices
- Higher compounding frequency and longer time increase growth.
- This is an estimate; real returns vary.
Limitations
- Assumes a constant rate and does not account for fees or taxes.
Related Tools
Related Articles
Percentage Change Calculator – Complete Guide & Free Online Tool A percentage change calculator measures how much a value increased or decreased as a percentage of its original value. Free online tool included. Read guide → Simple Interest Calculator – Complete Guide & Free Online Tool A simple interest calculator computes interest using the formula principal × rate × time, without compounding. Free online tool included. Read guide → Compound Interest Calculator – Complete Guide & Free Online Tool A compound interest calculator projects how an investment grows when interest is reinvested, with options for how often it compounds. Free online tool included. Read guide → Loan Calculator – Complete Guide & Free Online Tool A loan calculator estimates your monthly payment, total paid and total interest for a fixed-rate loan. Free online tool included. Read guide →
Frequently Asked Questions
What is compound interest?
Interest that is reinvested so that interest earns interest, leading to exponential growth.
What is the formula?
A = P × (1 + r/n)^(n·t), where n is compounds per year.
Is it free?
Yes, and it runs locally.