What Is CAGR? Compound Annual Growth Rate Explained
CAGR, or compound annual growth rate, is one of the most common ways to describe how an investment changed over time. This educational guide explains what CAGR represents, how it is calculated, and where it can be misleading.
In this guide
- What CAGR means and why it is used
- The CAGR formula and a worked example
- How CAGR differs from a simple average return
- When CAGR is useful—and when it can mislead
What CAGR means
CAGR is the constant yearly rate that would take a starting value to an ending value over a given number of years, as if it grew smoothly every year. Real markets rarely move in a straight line, so CAGR is best understood as a smoothed, illustrative summary rather than a description of what happened in any single year.
It is widely used because it makes returns over different time spans comparable on a per-year basis.
CAGR formula
The formula is:
CAGR = (Ending value / Beginning value)^(1 / years) − 1
Here, years is the length of the holding period. The result is usually expressed as a percentage.
Example calculation
Suppose a hypothetical investment grew from $10,000 to $16,000 over 4 years. The CAGR would be:
(16,000 / 10,000)^(1/4) − 1 = 1.6^0.25 − 1 ≈ 0.1247
That works out to roughly 12.5% per year. This is an illustrative example using round numbers, not a result for any specific asset.
CAGR vs average return
A simple (arithmetic) average return adds each year’s return and divides by the number of years. Because it ignores compounding, it can overstate the experience of a volatile investment.
For example, a +50% year followed by a −50% year averages to 0%, but the compounded result is actually a loss: $100 becomes $150, then $75. CAGR captures this compounding effect, which is why it is often a more honest single-number summary of historical growth.
Limitations of CAGR
- CAGR hides volatility — it says nothing about the ups and downs along the way.
- It is sensitive to the chosen start and end dates; different periods can produce very different numbers.
- It assumes a single lump sum held the whole time, so it does not describe recurring contributions well.
- It is descriptive of the past only and does not predict future results.
When CAGR is useful
CAGR is most useful for comparing the historical growth of different assets or scenarios over the same time period, and for translating multi-year changes into an easy-to-compare annual figure. Pair it with a drawdown or volatility measure to keep risk in view.
Key takeaway
CAGR is a smoothed, annualized summary of historical growth between two dates. It helps compare periods on a per-year basis, but it hides volatility and describes the past only—not future results.
Common mistakes
- Treating CAGR as a prediction of future annual returns
- Comparing CAGR figures calculated over different date ranges
- Ignoring drawdowns and volatility because the CAGR looks attractive
- Using CAGR alone when contributions were made at multiple dates (DCA)