A Larger Balance Can Still Buy Less: Nominal and Real Returns

Distinguish money from purchasing power

A nominal return measures the change in a money amount. A real return adjusts that result for a change in prices. The difference matters because an account can grow while the goods and services it could buy become more expensive. Inflation is not identical for every household: a broad index summarizes a basket, while your own spending mix may differ. Use the adjustment as context rather than claiming that one national figure describes every person’s experience or predicts future costs.

Use an exact simplified calculation

Imagine a hypothetical investment that grows 5% over one year while the relevant price level rises 3%. Ignoring fees and taxes, the real return is 1.05 divided by 1.03, minus one, or about 1.94%. Subtracting 3% from 5% gives a convenient approximate 2%, but it is not exact. If the investment instead earns 2% while prices rise 4%, purchasing power falls even though the nominal balance increases. These rates are invented examples, not statements about current market conditions.

Keep the comparison period consistent

An annual return should be paired with a price change for the same period. Do not compare a six-month account movement with a full-year inflation figure as though both cover identical dates. Distinguish total account growth from investment return when contributions and withdrawals occur. Also check whether a quoted performance figure includes distributions and fees. The purpose of the calculation is to compare like with like; mixing dates and definitions can create a convincing-looking percentage with little explanatory value.

Include costs without counting them twice

If a published return is already after certain fund expenses, subtracting those expenses again understates performance. Other fees or taxes may not be included. Write which costs are reflected in each number. For a $10,000 hypothetical balance, a $100 charge is 1% of that starting amount, but its precise effect depends on timing and other balance changes. Different tax circumstances can produce different after-tax outcomes. A simple real-return worksheet cannot substitute for an individualized tax calculation or a complete product disclosure.

Connect the measure to the goal

For an expense with a known date and amount, maintaining accessible funds may matter more than pursuing a higher uncertain real return. For a distant goal, purchasing-power assumptions help show why the future amount needed may differ from today’s price. Run several inflation scenarios and retain the original assumptions. This is planning under uncertainty, not a prediction that a specific asset will protect against inflation. No return measure removes the need to evaluate loss risk, liquidity, costs, and the consequences of needing the money earlier than expected.

Label the three outputs separately: nominal account performance, costs not already included, and purchasing-power adjustment. Write the price measure and dates beside the last figure. If a household’s goal is a specific service rather than a broad basket, also track that service’s price; its change need not match the overall inflation measure.