12
Repeated percentage change
See how growth or decline compounds over multiple periods.
Formula: starting value × (1 + rate ÷ 100)periods. Repeated percentage changes compound; they do not simply add.
FREE CALCULATOR · GROWTH
Compound Growth Calculator
A 10% gain followed by another 10% gain is not a 20% gain — it is 21%, because the second gain applies to the larger amount. This calculator compounds any rate over any number of periods.
How the compound growth calculator works
A 10% gain followed by another 10% gain is not a 20% gain — it is 21%, because the second gain applies to the larger amount. This calculator compounds any rate over any number of periods.
The formula
final = start × (1 + rate ÷ 100)^periods
Worked example
$1,000 growing 8% per year for 10 years: 1000 × 1.08^10 ≈ $2,158.93. The gains accelerate because each year's growth earns its own growth.
Where this comes in handy
- Investing: project portfolio growth at an assumed return.
- Inflation: see what 3% annual inflation does to prices over a decade.
- Business: model subscriber or revenue compounding.
- Debt: understand how unpaid balances snowball.
Compound Growth Calculator — frequently asked questions
What is compound growth?
Growth applied to an ever-larger base: each period's increase earns its own increase in later periods. It is why long time horizons matter so much in investing.
How is this different from simple repeated addition?
Simple addition would add the same dollar amount each period. Compounding adds a percentage of the current total, so the dollar amounts grow over time.
What is the Rule of 72?
A shortcut: divide 72 by the annual rate to estimate doubling time. At 8%, money doubles in roughly 9 years.
Does compounding work for losses too?
Yes — repeated percentage losses compound downward. Three straight 10% losses leave you at about 73% of the start, not 70%.
Why do small rate differences matter so much?
Because compounding magnifies them over time. Over 30 years, 7% vs 8% annual growth turns $10,000 into roughly $76,000 vs $100,600.