Understanding your average annual return result
| Metric | What it captures | Best used for |
|---|---|---|
| CAGR | The single compounding annual rate that matches the actual start-to-end change | Comparing investments over different time horizons on an apples-to-apples basis |
| Total return | The overall percentage gain or loss across the whole period, uncompressed into an annual rate | Understanding the total magnitude of gain or loss over the specific period held |
| Simple average annual return | Total return divided evenly by the number of years, ignoring compounding | A rough approximation only; typically overstates true annualized growth when returns compound |
- CAGR smooths a multi-year path into a single rate; it does not reveal how volatile the actual year-to-year returns were along the way — two investments can share the same CAGR while one experienced far larger swings than the other.
- This calculator assumes a single lump-sum starting value and a single lump-sum ending value with no additional contributions or withdrawals in between; adding cash flows during the period would require a different calculation (such as an internal rate of return).
- CAGR is a historical or hypothetical calculation based on the two values entered — it is not a forecast or guarantee of future performance.
What is CAGR (compound annual growth rate)?
CAGR answers the question: what single, constant annual growth rate — compounding every year — would turn a starting value into an ending value over a given time period? It is one of the most widely used metrics in investment performance reporting because it condenses a multi-year, often volatile return path into one comparable annualized figure, and it is a standard metric in the CFA Institute performance-measurement curriculum.
CAGR is not the same as the simple average of yearly returns, because it accounts for compounding — the fact that each year's growth builds on the previous year's ending balance rather than always on the original starting amount. When returns vary from year to year, the simple average of those yearly percentages is typically higher than the true CAGR, because simple averaging does not correct for the greater weight that compounding gives to periods with larger balances.
Total return, by contrast, is the overall percentage gain or loss from start to end regardless of how many years it took or how it was distributed across those years. CAGR essentially converts total return into an annualized, compounding-adjusted rate so investments over different time horizons can be compared on equal footing.
How to use this average annual return calculator
- Enter the starting value of the investment.
- Enter the ending value of the investment.
- Enter the number of years between the starting and ending values.
- Read the compound annual growth rate (CAGR), the total return over the full period, and the simple (non-compounded) average annual return for comparison.
- Example: an investment growing from $100,000 to $180,000 over 8 years has a CAGR of approximately 7.624%, a total return of 80%, and a simple average annual return of 10% (80% divided evenly across 8 years).
The formula behind CAGR
CAGR is calculated by taking the ratio of ending value to starting value, raising it to the power of one divided by the number of years (the nth root, where n is the number of years), and subtracting one. Total return is the simpler percentage change from start to end, and simple average annual return divides that total return evenly across the number of years without compounding.
Common mistakes
- Confusing simple average annual return with CAGR — the simple average typically overstates true compounded growth whenever returns vary from year to year.
- Applying CAGR to a period that included additional deposits or withdrawals, which this calculator does not account for; CAGR is designed for a single starting and single ending lump sum only.
- Treating CAGR as if it describes the actual return earned in every individual year, when it is a smoothed average — actual annual returns during the period could have been far more volatile.
- Using CAGR alone to judge an investment without also considering the risk taken to achieve it, since two investments with the same CAGR can have very different volatility.
- Forgetting that CAGR requires a positive starting value and a defined time period; it is undefined for periods of zero years or a zero or negative starting value.
よくある質問
What is the difference between CAGR and simple average return?
Simple average return adds up each year's percentage return and divides by the number of years, treating every year's contribution equally without regard to compounding. CAGR instead finds the single steady rate that, compounding annually, would take the starting value to the ending value — and because compounding weights later years more heavily on a larger base, CAGR is typically lower than the simple average when returns vary year to year.
Why is CAGR considered more accurate than simple average return?
CAGR accounts for the compounding effect — the fact that gains and losses each year apply to the previous year's ending balance, not the original starting amount. Simple average return ignores this compounding relationship, which can make it a misleading measure of an investment's true annualized growth rate, particularly when yearly returns are volatile.
Can CAGR be used to compare two different investments?
Yes, CAGR is widely used precisely because it standardizes returns over different time horizons into a single comparable annualized rate. However, it should still be interpreted alongside a measure of volatility or risk, since two investments can share an identical CAGR while differing substantially in how bumpy the path to that result was.
Does this calculator account for additional contributions during the period?
No. This calculator computes CAGR between a single starting value and a single ending value, assuming no additional deposits or withdrawals occurred in between. Investments with periodic contributions or withdrawals require a different calculation, such as a money-weighted or internal rate of return, to accurately reflect performance.
What does a CAGR of 7.624% actually mean?
It means that, if the investment had grown at a perfectly steady 7.624% annual rate every single year, compounding on itself, it would have reached the same ending value from the same starting value over the same number of years as the actual (possibly uneven) path did. It is a smoothed, standardized way of expressing the overall growth rate, not a claim that the return was exactly 7.624% in every individual year.
参考文献
- CFA Institute. CFA Program Curriculum — Performance Measurement: Compound Annual Growth Rate and Return Calculation Methods.
- U.S. Securities and Exchange Commission (SEC), Investor.gov. Understanding investment returns and compounding. investor.gov.
- Bodie Z, Kane A, Marcus AJ. Investments. McGraw-Hill Education (standard reference for annualized and compounded return calculations).
- Financial Industry Regulatory Authority (FINRA). How to read investment performance reports — annualized vs. cumulative returns. finra.org.