AtlasCalc💰 FinancebeginnerOffline
Compound Interest
Future value with compound interest and optional monthly contributions.
Inputs
Enter your values below.
Result
Your answer appears here.
Enter values and press Calculate — the result appears here.
How it works
The formula behind this calculator.
A = P × (1 + r/n)^(n·t)
- P
- Initial principal
- r
- Annual interest rate (%)
- n
- Compounding periods per year
- t
- Time in years
Compound interest is interest earning interest. The Rule of 72 says money doubles in roughly 72 / r% years (e.g. 7% → ~10.3 years).
Example: $10,000 at 7% compounded monthly for 10 years → $20,096
Ref: Exponential growth
Tips
- 💡 Compounding frequency matters. Monthly compounding earns more than annual for the same nominal rate.
- 💡 The Rule of 72: years to double ≈ 72 / annual rate %. At 7%, your money doubles in ~10.3 years.