Compound Interest Calculator
Calculate compound interest, total amount and compare with equivalent simple interest using different compounding frequencies.
✓ Runs in your browser · Updated 2026-03-31Enter values and click Calculate Interest to see results
How to Use the Compound Interest Calculator
Enter your principal amount, annual interest rate, time period in years and choose the compounding frequency. Click Calculate to see the compound interest, total maturity amount and how it compares to simple interest.
What Is Compound Interest?
Compound Interest (CI) is interest calculated on the initial principal and on the accumulated interest from previous periods. Albert Einstein allegedly called it "the eighth wonder of the world." The more frequently interest is compounded, the higher the returns.
Compound Interest Formula
A = P × (1 + r/n)n×t
CI = A − P
- P — Principal amount
- r — Annual interest rate (decimal)
- n — Number of times compounded per year
- t — Time in years
The Power of Compounding — Example
₹1,00,000 invested at 10% for 20 years:
- Simple Interest: ₹2,00,000 (₹1L interest)
- Compound (Yearly): ₹6,72,750 (₹5.73L interest)
- Compound (Monthly): ₹7,32,807 (₹6.33L interest)
Monthly compounding earns ₹60,057 more than yearly compounding over the same period!
CI vs SI — When to Use Which
- Compound Interest applies to most bank deposits (FDs, RDs), mutual fund SIPs, and PPF.
- Simple Interest is used in some short-term loans and flat-rate EMI schemes.
- For loan EMIs on reducing balance, use our EMI Calculator.
Frequently Asked Questions
What is the compound interest formula?
A = P × (1 + r/n)^(n×t), where P is principal, r is annual rate, n is compounding frequency per year, and t is time in years. CI = A − P.