See how money grows with compound interest. Choose how often interest is compounded, add regular contributions, and adjust for inflation.
Basic Compound Interest Calculation
Advanced Compound Interest Analysis
Advanced Investment Planning & Analysis
What this compound interest calculator does
- Basic: initial investment, interest rate, years and compounding frequency (annually to daily) to the final amount, interest earned, growth multiple and effective annual rate.
- Intermediate: adds regular contributions (monthly, quarterly, semi-annually or annually).
- Advanced: adds monthly contributions and an inflation rate to show the real (inflation-adjusted) value and how many years it takes to double.
How it is calculated
Final amount = principal × (1 + rate ÷ n)n × years, where n is the number of times interest is compounded per year. With contributions, the balance grows at the chosen compounding frequency and each contribution is added at the end of its period. Years to double = ln 2 ÷ ln(1 + rate).
Worked examples: $10,000 at 5% for 10 years compounded monthly grows to about $16,470, with $6,470 of interest. If you also add $100 a month for 10 years, the total is about $31,725 with annual compounding, $31,998 with monthly compounding and $32,023 with daily compounding.
Things to keep in mind
The rate is assumed to stay the same for the whole period, which real investments rarely do. The interest rate must be at least 0.1%. Taxes and fees are not included. These results are estimates for general information only and are not financial, tax, investment or legal advice. Real products have fees, rules and rates that differ, so check the details with your lender, provider or a qualified adviser.
Frequently asked questions
Does compounding more often make a big difference?
It helps a little. Going from annual to daily compounding adds only a small amount, while the rate and the time matter far more.
What is the effective annual rate?
The yearly growth rate after compounding is taken into account. It is slightly higher than the stated rate when interest compounds more than once a year.
Looking for more? See all our free financial calculators.