Compound Interest Calculator
Visualize your investment growth year by year. Adjust principal, monthly contributions, rate, and compounding frequency — the chart updates instantly.
International standards: Choose USD, EUR, TRY, or GBP— amounts format with locale-aware rules for real-world use across regions.
End Balance
$0after 20 years
Total Contributed
$0Interest Earned
$0Investment Inputs
ROI
+132.6%
Doubles in
10.3 yrs
Investment Growth
Hover over the chart for a year-by-year breakdown
Yearly Milestones
The Power of Compounding
at current rate & contribution10 Years
$107.1K
$70.0K contributed
$37.1K earned
20 Years
$302.4K
$130.0K contributed
$172.4K earned
30 Years
$694.7K
$190.0K contributed
$504.7K earned
Compound Interest Formula
A = P × (1 + r/n)nt + PMT × [(1 + r/n)nt − 1] / (r/n)
- A
- Final amount (balance at end of term)
- P
- Principal — initial investment
- PMT
- Periodic contribution (per compounding period)
- r
- Annual interest rate (decimal, e.g. 0.07 = 7%)
- n
- Compounding periods per year (12 / 4 / 1)
- t
- Time in years
Rule of 72: Divide 72 by your annual rate to estimate how many years it takes to double your money. At 7%, your investment doubles every ≈ 10.3 years.