Compound Interest Calculator
See how a starting amount and monthly contributions grow over time with compound interest.
Future Value
$144,573
- Total contributions
- $48,000
- Total interest
- $86,573
Assumptions
- Constant annual return rate
- Interest compounds monthly
How it's calculated
Future value = principal × (1+r)^n + contribution × ((1+r)^n − 1) / r.
Worked example
$10,000 starting with $200/month at 7% over 20 years grows to a substantial future value, shown live above.
Frequently asked questions
Is a 7% return guaranteed?
No — this is an illustrative assumption you can change. Real investment returns vary and are never guaranteed.