Compound Growth Calculator
Enter a starting amount and a monthly contribution, pick a return assumption and a horizon, and see the year-by-year projection. The math is the same annuity formula used throughout our guides.
Your inputs
Projected balance
$0
Total you contribute
$0
Investment growth
$0
Year by year
Each bar shows the projected balance at the end of that year.
The formula behind the numbers
With monthly contributions the projection uses the future value of an annuity. A starting amount compounds on its own at the same monthly rate:
PMT is the monthly contribution, r is the annual return divided by 12, n is the number of months, and P is the starting amount. The bars above apply the formula one month at a time, so the chart and the totals always agree.
How to read the result
Treat every figure as an illustration, not a prediction. A 7% return is a rough long-run assumption for a stock-heavy portfolio, not a guarantee: individual years swing widely, and a weak sequence early on changes the ending balance. Contributions are assumed to arrive at the end of each month, and the model ignores taxes, inflation, and fund fees.
To see how the same math shapes a beginner routine, read dollar-cost averaging explained or the $1,000 step-by-step plan.