Compound Interest Calculator
Use the Compound Interest Calculator in your browser.
Methodology & standardsRuns on your device
Inputs
Results update liveInterpretation
How Compound Interest works
The calculator combines compound growth on the starting balance with contributions made at the end of each whole month. It converts the selected annual, quarterly, monthly, or daily compounding convention into an equivalent monthly rate before valuing those monthly contributions.
Example
Key features
A realistic scenario showing how the calculation guides a practical decision.
Formula
A = P(1 + i)^m + PMT × [((1 + i)^m − 1) / i], where i is the equivalent monthly rate and m is the number of months.
- Compound growth on an initial balance
- Monthly contributions with an explicit month-end assumption
- Annual, quarterly, monthly, or daily nominal compounding
- A separate view of total contributions and estimated growth
Watch out
Common mistakes
- A projection is sensitive to the assumed rate, fees, taxes, and investment volatility. Use a range of rates when making a savings plan rather than relying on one forecast.