CalcWealth

Free Average Return Calculator — Portfolio Mean Returns

Enter a series of annual returns to instantly calculate the arithmetic mean and geometric mean (CAGR) for any portfolio. Understand the difference and which measure best reflects real investment growth.

This free average return calculator computes both the arithmetic mean and the geometric mean (CAGR) from a sequence of annual investment returns. See exactly how volatility drag reduces your effective return over time. No sign-up required.

What Is Average Return?

The average return is used to evaluate portfolio performance over multiple periods. There are two types that matter for investors: the arithmetic mean, which simply averages all returns, and the geometric mean (CAGR), which accounts for compounding and is the more accurate measure of multi-year performance.

The difference between the two is called volatility drag. A portfolio that gains 100% one year and loses 50% the next has an arithmetic mean of 25% — but the investor has exactly $0 in net gains. The geometric mean correctly reports 0%, reflecting the actual outcome. For any investment held over multiple years, always use the geometric mean.

The geometric mean is equivalent to CAGR — the constant annual rate that would produce the same total growth from beginning to end. It is the standard metric used by the SEC for fund performance disclosure.

How to Use This Calculator

  1. 1

    Enter Your Annual Returns

    Type each year's return as a percentage, separated by commas or on new lines. Include the sign: positive returns as "26" or "+26", negative returns as "-4.4". You can enter any number of years.

  2. 2

    Review Arithmetic Mean

    The arithmetic mean is the simple average of all your returns. It overstates actual performance when returns are volatile. Use it only to estimate the expected return for a single future period.

  3. 3

    Review Geometric Mean (CAGR)

    The geometric mean shows the constant annual return that matches the actual total growth of your portfolio. This is the number that matters for long-term wealth building — it correctly accounts for the compounding of gains and losses.

  4. 4

    Observe the Volatility Drag

    The gap between arithmetic mean and geometric mean is the volatility drag. The bigger the swings in your returns, the larger this gap. Stable, consistent returns have a much smaller drag than volatile ones — which is why diversification improves real-world outcomes.

Average Return Formulas

Arithmetic Mean

AM = (R₁ + R₂ + ... + Rₙ) / n

Example: Returns of +26%, +18.4%, −4.4%, +26.9%, +11.7% → AM = (26 + 18.4 − 4.4 + 26.9 + 11.7) / 5 = 15.7%

Geometric Mean (CAGR)

GM = [(1+R₁)(1+R₂)···(1+Rₙ)]^(1/n) − 1

Example: Same S&P 500 returns → [(1.26)(1.184)(0.956)(1.269)(1.117)]^(1/5) − 1 = 14.5%

The gap between 15.7% (arithmetic) and 14.5% (geometric) is the 1.2% annual volatility drag caused by the negative year. Over 5 years on a $10,000 portfolio, this drag equals roughly $700 in lost growth.

Real-World Examples

Three portfolios showing how volatility affects average return measurements.

S&P 500 — 5-Year Returns (2019–2023)

Returns: +26%, +18.4%, −4.4%, +26.9%, +11.7%
Arithmetic mean: 15.7% |  Geometric mean (CAGR): 14.5%
The 1.2% drag comes from the one negative year pulling the compound growth down relative to the simple average.

Volatile Portfolio — Zero Net Growth

Returns: +50%, −33%, +50%, −33%
Arithmetic mean: 8.5% |  Geometric mean: 0.0%
The arithmetic mean suggests strong growth, but the portfolio hasn't grown at all. A +50% gain followed by a −33% loss returns exactly to the starting value every two years.

Stable Portfolio — Consistent Returns

Returns: +7%, +8%, +6%, +9%, +7%
Arithmetic mean: 7.4% |  Geometric mean: 7.39%
When returns are consistent and low-volatility, the arithmetic and geometric means are nearly identical. This illustrates why diversification and stability improve long-run compounded outcomes.

Frequently Asked Questions

What is the difference between arithmetic mean and geometric mean?
The arithmetic mean simply adds up all returns and divides by the number of periods. The geometric mean (also called CAGR) multiplies (1 + each return) together, takes the nth root, and subtracts 1. For example, returns of +50% and −33% give an arithmetic mean of 8.5% but a geometric mean of 0% — the portfolio is exactly where it started. The geometric mean is always less than or equal to the arithmetic mean.
Which average return should I use for investments?
Use the geometric mean (CAGR) to measure how much an investment actually grew over time — it accounts for the compounding effect and gives an accurate picture of wealth accumulation. Use the arithmetic mean only to estimate expected future returns for a single upcoming period. Mutual funds and ETFs are required by the SEC to report returns as CAGR, not arithmetic averages, for this reason.
What is volatility drag and why does it matter?
Volatility drag (also called variance drain) is the gap between the arithmetic mean and the geometric mean caused by large swings in returns. A portfolio that gains 100% then loses 50% has an arithmetic mean of 25% but a geometric mean of 0% — you haven't made any money. The more volatile the returns, the larger the drag. This is why reducing volatility through diversification can improve long-run portfolio performance even without changing the average return.
Is average return the same as CAGR?
CAGR (Compound Annual Growth Rate) is the same as the geometric mean return when calculated over annual periods. Both represent the constant annual rate that would produce the same total growth from start to finish. CAGR is the industry-standard measure for comparing fund performance, index returns, and any investment held over multiple years.
What is the historical average return of the S&P 500?
The S&P 500's long-run geometric mean (CAGR) is approximately 10% nominal and 7% real (inflation-adjusted) per year. The arithmetic mean is slightly higher — around 11–12% nominal — due to year-to-year volatility. These figures span the 1926–2024 period; any 10-year window can differ significantly. Past performance does not guarantee future results.
How do I use average return to compare mutual funds?
Always compare funds using the geometric mean (CAGR) over the same time period — 1-year, 5-year, and 10-year returns. Ignore arithmetic-mean figures in marketing materials. Also check the standard deviation of returns: a fund with a 10% CAGR and low volatility will outperform a fund with a 10% CAGR and high volatility on a risk-adjusted basis. Use our investment calculator to project future values at different CAGRs.

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