Compound interest calculator
Start early or start late?
This one is pure maths, not history: a fixed rate that you choose. It shows how much of the end result is money you put in and how much is growth on growth.
Total–
Started later–
Money put in–
Growth–
Growth
- Total value
- Money put in
- Started later
The dark green area is money put in; the light area above it is growth. Hover, tap or use the arrow keys on the chart.
Maths, not a forecast. A fixed rate is an assumption: real markets never deliver a straight line, as the what-if calculator shows. Interest is compounded monthly at the annual rate divided by 12; contributions are added at the end of each month. No fees, taxes or inflation. Information only, not financial advice.
Year by year
Formula: FV = P(1 + r/12)12t + C · ((1 + r/12)12t − 1) / (r/12)