The compound annual growth rate, or CAGR, expresses how much an investment grew per year on average, as if it had climbed at one steady rate. It is the cleanest way to compare investments held over different periods. This guide explains how CAGR is calculated and what it does and does not tell you.
What CAGR measures
CAGR answers a simple question: at what constant annual rate would your starting amount have to grow to reach its ending value over the period? It smooths out the year-to-year bumps into a single figure. Because it accounts for compounding, it is more accurate than simply averaging each year's return. That makes it the standard yardstick for comparing multi-year performance.
How it is calculated
CAGR is found by dividing the ending value by the beginning value, raising the result to the power of one divided by the number of years, and subtracting one. For example, growing from $10,000 to $16,000 over five years gives a CAGR of about 9.9%. The formula uses only the start value, end value, and time, so it is easy to compute. It always reflects true compounding rather than a plain average.
CAGR versus average return
A simple average of annual returns can be misleading because it ignores compounding and the order of gains and losses. A 50% gain followed by a 50% loss averages to zero but actually leaves you down 25%, and CAGR correctly captures that as a negative rate. This gap between the arithmetic average and CAGR grows with volatility. When someone quotes an average return, check whether they mean CAGR.
What CAGR hides
CAGR presents a smooth line, but real investments rarely grow evenly, so it conceals the volatility you actually lived through. Two investments can share the same CAGR while one was calm and the other wild. It also ignores contributions and withdrawals made along the way, which a money-weighted return would capture. Use CAGR to compare growth rates, but pair it with a look at the ups and downs.
You invest $10,000 and it grows to $16,000 after five years. Dividing 16,000 by 10,000 gives 1.6, and raising that to the power of one-fifth then subtracting one yields a CAGR of about 9.9% per year. That single rate lets you compare it fairly against an investment held for a different number of years.
Key takeaways
- CAGR is the single constant annual rate that connects a starting value to an ending value.
- It accounts for compounding, unlike a simple average of yearly returns.
- Calculate it as end divided by start, raised to the power of one over the years, minus one.
- A big gap between average return and CAGR signals high volatility.
- CAGR smooths over the real bumps and ignores mid-period cash flows.
Common mistakes
- Quoting a simple average of yearly returns as if it were the true compound rate.
- Comparing two investments by total gain without annualizing for different time spans.
- Trusting a smooth CAGR while forgetting the volatility it hides.
FAQ
Is CAGR the same as average annual return?
No. CAGR reflects compounding and is usually lower than a simple arithmetic average when returns are volatile.
Does CAGR account for deposits I made along the way?
No. It only uses the start and end values, so for portfolios with contributions a money-weighted return is more accurate.