About the Real Rate of Return Calculator
This real rate of return calculator converts the headline (nominal) return on an investment into what it actually adds to your purchasing power. Enter the annual return, the expected inflation rate and the tax rate you pay on the gains, and it shows the inflation-adjusted return, the after-tax return and the after-tax real return — the number that really matters for long-term goals.
Use it to compare a savings account, bond or stock portfolio on a like-for-like basis, to check whether a “high” interest rate is beating inflation, or to pick a realistic growth rate for retirement planning in today’s money. The chart projects an amount forward in nominal dollars and in today’s dollars so you can see how far the two drift apart.
It uses the exact Fisher relationship rather than the quick “return minus inflation” shortcut, and assumes returns are taxed every year at a flat rate (as with interest income). Gains in tax-deferred accounts or taxed only on sale will do somewhat better than the after-tax figure shown.
With the default inputs, the after-tax real return is 3.69%. Change any value above to recalculate instantly.
How to use the real rate of return calculator
- 1Enter the nominal annual return you expect or have earned.
- 2Enter the inflation rate — use recent CPI or your long-term assumption.
- 3Enter the tax rate on the returns, or 0 for tax-free accounts.
- 4Optionally add an amount and number of years to project growth.
- 5Compare the after-tax real return with your other options.
Formula and method
The Fisher equation links nominal and real returns: (1 + nominal) = (1 + real) × (1 + inflation). Rearranging gives the exact real return (1 + r) ÷ (1 + i) − 1. The popular shortcut r − i slightly overstates the real return, and the gap grows when inflation is high.
For the after-tax figure, tax is applied to the nominal return first — you pay tax on the whole gain, including the part that only keeps up with inflation — so r becomes r × (1 − t) before inflation is removed. Future values compound the after-tax nominal return, and the real value divides by (1 + i) raised to the number of years.
- r
- Nominal annual return (decimal)
- i
- Annual inflation rate (decimal)
- t
- Tax rate applied to returns (decimal)
Worked examples
8% return, 3% inflation, 15% tax, $10,000 for 20 years
Before tax, 1.08 ÷ 1.03 − 1 = 4.85% real. Tax cuts the nominal return to 8% × 0.85 = 6.8%, and 1.068 ÷ 1.03 − 1 = 3.69% after-tax real. $10,000 grows to about $37,276 in 20 years, but that only buys what roughly $20,639 buys today.
Savings account at 4.5% with 3.2% inflation and 24% tax
A 4.5% rate looks healthy, but after 24% tax it is 3.42%, and dividing 1.0342 by 1.032 leaves a real return of just 0.21% a year — barely ahead of inflation.
Tax-free account: 7% return, 2.5% inflation
With no tax, the real return is 1.07 ÷ 1.025 − 1 = 4.39%. $50,000 compounds to about $380,613 in 30 years, equal to roughly $181,454 in today’s money.
Frequently asked questions
What is the real rate of return?+
It is the return on an investment after removing the effect of inflation — the increase in what your money can actually buy. A 6% return with 4% inflation is only about a 1.9% real return.
Why not just subtract inflation from the return?+
Subtracting is a close approximation when rates are low, but the exact Fisher formula divides: (1 + r) ÷ (1 + i) − 1. At 10% return and 8% inflation the shortcut says 2%, while the true real return is 1.85%.
Should taxes be applied before or after inflation?+
Before. Tax is charged on the full nominal gain, including the part that merely offsets inflation, which is why high inflation hurts taxable investors more. This calculator taxes the nominal return and then adjusts for inflation.
What inflation rate should I use?+
For historical returns, use the actual CPI change over the same period. For planning, many people assume 2–3% a year, in line with central bank targets, and test a higher rate to see how sensitive the plan is.
Can a real return be negative?+
Yes. Whenever the after-tax return is lower than inflation — common for cash savings in high-inflation years — your balance grows in dollars but buys less each year.
Results are estimates for educational purposes and are not financial advice. Rates, fees and terms vary — confirm with your lender or a licensed advisor before making decisions.