What is compound interest?
Compound growth means returns can earn additional returns. This model assumes a fixed annual nominal rate compounded monthly and deposits at the end of each month.
Worked example
Example: start with $10,000 and add $200 per month. Change the rate and time horizon to see how the estimate responds.
Assumptions and limitations
Investment returns are not guaranteed; taxes, inflation, volatility and fees are excluded.
How to use this calculator
Enter the requested values, check the units, and press Calculate now. Adjust one input at a time to compare scenarios. The result updates only when you press the button again.
For educational purposes only. Verify important financial or health decisions with a qualified professional.
Further reading: Simple vs. compound interest
Compound growth formula
For monthly compounding, future value = P(1 + r)^n + C × [((1 + r)^n − 1) ÷ r]. P is starting balance, C is the contribution made at the end of each month, r is the monthly rate, and n is the number of months. At 0%, future value = P + Cn.
Frequently asked questions
Does this predict investment returns?
No. The model assumes a constant rate and does not account for market volatility, taxes, fees or inflation.
Can I use this calculator for free?
Yes. CalcTrustHub calculators are free to use and do not require an account. Results are estimates based on your inputs.
Why contribution timing matters
This model treats contributions as occurring at the end of each month, with a constant annual rate divided into monthly periods. Contributions at the beginning of each month would earn slightly more interest. Actual investment returns fluctuate and are not guaranteed.
Does the result include inflation or taxes?
No. The estimate is nominal and excludes taxes, fees and the effect of inflation on purchasing power.