Future value--
Contributions and interest--
Compound Interest Calculator
Compound Interest Calculator gives a practical planning estimate for monthly payments, interest, savings, or future value. Verify important financial decisions with lender or account documents.
Updated May 2026No signup requiredBuilt for mobile
Calculator
How to use this calculator
- Enter your values in the calculator fields.
- Check that the units and percent formats match what the label asks for.
- Click Calculate to update the result.
- Use Reset Calculator to restore the starting example.
Formula or calculation method
Future value is calculated by compounding the balance each period.
Contributions are added on the monthly schedule and then compounded.
Interest earned = future value - starting amount - total contributions.
Worked example
$5,000 plus $200 per month for 10 years at 6% compounded monthly grows to about $41,735.
Practical planning tips
- Savings goals
- Investment planning
- Interest comparisons
- Long-term projections
- Contribution planning
Common mistakes to avoid
- Treating estimates as lender quotes
- Forgetting taxes, fees, or insurance
- Using APR rules incorrectly for special financing
FAQ
Compound Interest Calculator questions
Is this calculator exact?
It is a practical estimate based on the values you enter. Verify important decisions with the official source, lender, school, product label, or professional guidance when needed.
Why did I get an error?
The calculator checks for blank fields, invalid numbers, impossible negative values, and divide-by-zero situations. Review the message and adjust the input.
Can I use this calculator on my phone?
Yes. The inputs, buttons, and result cards are built to work on mobile screens.
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