Compound Growth Calculator

How to use this calculator

Adjust the inputs to your own scenario, then review the result alongside the assumptions below. The $ symbol is a currency label; the tool does not convert exchange rates.

Worked example

At 0% return, a $10,000 initial balance and $100 contributed monthly for 10 years produce $22,000, entirely from contributions. Changing the return input adds hypothetical growth or losses.

The formula

Monthly rate = (1 + annual return)^(1/12) − 1. Each month: new balance = previous balance × (1 + monthly rate) + contribution.

What the result means

The chart separates total contributed capital from the modeled balance. The difference is hypothetical growth, which may be negative. A historical trading return should not be treated as a dependable future annual return.

Assumptions and limitations

Assumes a constant effective annual return, monthly compounding, and contributions at the end of each month. Returns are reinvested. Inflation, taxes, fees, withdrawals, and variable market returns are excluded. Real investment returns are uneven and can be negative.

Explore the SEC’s compound interest calculator for another approach to contribution and compounding scenarios.

Common questions