CAGR Calculator
Last updated: November 14, 2026
Direct answer. CAGR = ((Ending value ÷ Starting value)^(1 ÷ years) − 1) × 100. A move from 100 to 121 in 2 years is a 10% CAGR.
CAGR, the compound annual growth rate, is the single annual rate that would take a starting value to an ending value over a stated number of years, with compounding once a year. U.S. investors and operators use it to summarize a path that was not necessarily smooth. This calculator applies that formula; it is not a market forecast.
CAGR Calculator
Compound annual growth rate is the constant annual rate that takes a starting value to an ending value over a number of years.
Result
Key takeaways
- CAGR is the constant annual rate that compounds from the start value to the end value.
- 100 to 121 in 2 years is a 10% CAGR, because 100 × 1.10 × 1.10 = 121.
- The starting value must be greater than 0, years must be greater than 0, and the ending value cannot be negative.
- CAGR ignores the path between the two dates; a bumpy series can share a CAGR with a smooth one.
How to use this calculator
- Enter the starting value.
- Enter the ending value in the same unit.
- Enter the number of years, which may be a fraction if you are using a part-year period consistently.
The formula
The ratio of the ending value to the starting value is raised to 1 ÷ years, then 1 is subtracted and the result is written as a percent. Units of the two values must match; the result is a percent per year.
Worked examples
| Start | End | Years | CAGR |
|---|---|---|---|
| 100 | 121 | 2 | 10% |
| 100 | 100 | 5 | 0% |
| 80 | 20 | 1 | −75% |
The ratio is 1.21. The square root of 1.21 is 1.10. CAGR is (1.10 − 1) × 100 = 10%.
100 to 100 in any positive number of years has a 0% CAGR.
When this is useful in the United States
A savings or revenue series that started at 100 and ended at 121 two years later can be summarized as 10% a year, even if the middle year was uneven.
A product price, a headcount, or a website metric can use the same formula when both ends are positive and in the same unit.
CAGR is not the same as an average of yearly percent changes. Averaging +50% and −50% is not a 0% CAGR on the original base.
Common mistakes
- Dividing the total percent change by the number of years and calling it CAGR. 21% over two years is not a 10.5% CAGR; the compound rate is 10%.
- Using a start of 0, which would make the ratio undefined.
- Entering years as 0.
CAGR does not include deposits, withdrawals, dividends, or taxes unless you have already folded them into the start and end values. A start must be greater than zero because the formula divides by it. An end of zero over a positive number of years is a −100% CAGR, which the math allows; a negative end is rejected because a real compound growth factor would not land below zero from a positive start in this simple model. CAGR is a compact summary, not a promise that a value grew smoothly at that rate each year. Two very different paths can share the same start, end, and CAGR. If you need the year-by-year rates, calculate those separately and do not expect their simple average to equal the CAGR. Time must be in years for the percent to be an annual rate; 18 months is 1.5 years, not 18. When a series includes new deposits, the start and end values already have to reflect the quantity you mean to describe, or the CAGR will mix growth with added cash. This page does not model those cash flows. When the time span is not a whole number of years, keep the years field in year units, such as 2.5 for two and a half years, so the result remains an annual rate. Entering 30 to mean 30 months would understate the rate because the formula would treat it as 30 years. If you only know a total percent change and a number of years, you still need the start and end values, or you can set the start to 100 and the end to 100 plus that total percent. For a 21% rise over two years that is 100 and 121, which is the 10% CAGR already shown in the table, not 10.5%.
Frequently asked questions
What is the CAGR from 100 to 121 in 2 years?
It is 10%.
Is CAGR a guarantee of next year’s return?
No. It only describes the constant rate implied by the two values and the time span you entered.
Can CAGR be negative?
Yes, if the ending value is lower than the start and still at least 0.
How is this related to inflation compounding?
The same (1 + rate)^years structure appears in the inflation calculator. CAGR solves for the rate; the inflation tool applies a rate you already have.