Real Rate of Return: Formula and Examples

The real rate of return is the return on an investment after adjusting for inflation. It measures what your money can actually buy at the end of the period rather than how much the account balance grew, which is why it is the number that matters for long-term goals like retirement.

A portfolio that gained 7% in a year when inflation ran 3% did not really grow 7%. Your purchasing power grew closer to 4%, and over a multi-decade horizon that gap compounds into a very large difference.

Real Rate of Return Formula

The exact formula divides growth by inflation rather than subtracting it:

Real Rate of Return = ((1 + Nominal Rate) / (1 + Inflation Rate)) - 1

Using a 7% nominal return and 3% inflation:

(1.07 / 1.03) - 1 = 0.0388, or 3.88%

The quick version most people use is simple subtraction:

Real Rate (approximate) = Nominal Rate - Inflation Rate

That gives 4% here, close enough for a rough check. The approximation drifts as rates get larger, though, and in high-inflation periods it overstates your real return meaningfully.

For everyday estimates the shortcut is fine. For projections that compound over decades, use the exact formula.

Why Real Returns Compound Into Large Differences

Over a single year the distinction looks academic. Over a career it is not.

Invest $100,000 for 30 years at a 7% nominal return and you end with about $761,000. That figure is in future dollars, though. If inflation averaged 3% over the same period, the purchasing power of that balance is roughly $313,000 in today’s terms, which is exactly what $100,000 growing at the 3.88% real rate produces.

Both numbers describe the same outcome. Only one of them tells you what you can buy.

Taxes Make the Real Return Lower Still

Taxes are assessed on nominal gains, not real ones, which quietly reduces your after-tax real return by more than the headline tax rate suggests.

Say you earn 5% nominal in a taxable account while inflation runs 3%. Your real pre-tax return is about 1.94%. At a 22% marginal rate you owe tax on the full 5%, roughly 1.1 percentage points, leaving an after-tax real return near 0.87%. You were taxed on gains that partly represented inflation rather than genuine increases in purchasing power.

This is one reason tax-advantaged accounts matter more than a comparison of tax rates alone implies, and why the account a given asset sits in affects your real outcome. Modeling your projected returns and tax treatment together, rather than assuming a flat rate on everything, gives a more honest picture of what you keep; you can compare account placement and withdrawal order in ProjectionLab’s tax analytics.

Frequently Asked Questions

What is the formula for the real rate of return? ((1 + nominal rate) / (1 + inflation rate)) - 1. With a 7% nominal return and 3% inflation, that works out to 3.88%.

Can I just subtract inflation from my nominal return? For a quick estimate, yes. The subtraction shortcut is accurate to within roughly a tenth of a percentage point at typical rates, but it overstates the real return as rates rise, so use the exact formula for long-range projections.

What is a realistic real rate of return for a stock portfolio? US equities have delivered roughly 6-7% annualized real returns over very long historical periods, though multi-decade stretches have come in well above and well below that. Many planners assume 4-5% real for a diversified portfolio to build in margin.

Can the real rate of return be negative? Yes, whenever inflation exceeds your nominal return. A savings account paying 2% during 4% inflation delivers a real return of about -1.9%, meaning the balance grows while its purchasing power shrinks.

Should I use nominal or real returns in my retirement projections? Either works as long as you are consistent. If you project in real terms, keep expenses in today’s dollars and use real return assumptions. If you project in nominal terms, inflate future expenses and use nominal returns. Mixing the two is a common source of badly wrong projections.