Money guide · Investing basics, fees, and risk
Real vs. nominal return: adjust for inflation
Calculate an inflation-adjusted investment return and distinguish market growth from gains in purchasing power.
How it works
The exact relationship is multiplicative because both the asset balance and price level change. Subtracting inflation from nominal return is a useful approximation for small rates, but not the exact result. Compare the same start and end dates and state whether the nominal return is before or after fees and taxes.
A worked example
If $10,000 grows 8% to $10,800 while prices rise 5%, the ending balance has about $10,285.71 of starting-period buying power: $10,800 / 1.05. Real return is about 2.86%, not exactly 3%. A positive nominal gain can also become a negative real return if inflation exceeds the comparable after-cost gain.
What to compare
Use an appropriate inflation index for the comparison and recognize that personal expenses may change differently from CPI. Include dividends and interest consistently in investment returns, and avoid counting deposits as gains. For multiyear results, compare compounded return and cumulative price changes over the same horizon rather than pairing an annual return with several years of inflation.
A common mistake to avoid
Do not subtract inflation from a figure that is already expressed in constant dollars. Avoid mixing a pretax market return with after-tax spending needs without explaining the difference. Historical real returns describe a past period; they do not establish what an investment will deliver in the next period.
Can my balance rise while buying power falls?
Yes. If the relevant price level rises more than your comparable nominal after-cost growth, the real result is negative despite a larger dollar balance.
Sources and further reading
Connect this to inflation
Inflation changes the spending power of money over time. Read the related inflation explainer, or explore historical market returns using your own assumptions.