Real Rate of Return Calculator

Your real rate of return tells you whether an investment built wealth or just kept pace with rising prices. The nominal return is the dollar gain on paper; the real return strips out inflation so you can see what your money will actually buy. This calculator uses the Fisher equation to work that number out.

What real rate of return means

Say your portfolio earned 10% last year and inflation ran at 7%. On paper you're up 10%, but a basket of groceries that cost $100 now costs $107. Your purchasing power didn't grow by 10%; it grew closer to 2.8%. That 2.8% is the real rate of return, and the Fisher equation gives it to you:

A 12% nominal return looks heroic until you find out inflation averaged 9% across the same stretch. Most of that gain was just keeping up. The flip side is true too: during low-inflation years, a modest 5% nominal return is mostly real wealth.

How to use this calculator

Put your investment's nominal return into the first field, the headline figure on your account statement. Enter the inflation rate over the same window. CPI is the standard reference for most countries, and the period needs to match (annual return paired with annual inflation, monthly with monthly).

You can also run it backwards. If you know the real return you achieved and the inflation rate, the calculator solves for the nominal rate you must have earned.

Where this number matters

Comparing returns across decades is the clearest case. A 15% return in 1980, when inflation pushed 13%, was barely better than break-even. A 7% return today with 2% inflation is meaningfully better. Ignoring inflation flips the ranking entirely.

Retirement math leans on real returns harder than most planning does. A 25-year withdrawal plan calculated in nominal dollars will overstate what the portfolio can sustain. Planners assume a real return (often 4 to 6% for a diversified portfolio) so the dollar's loss of value is already baked into the math. Bond investors care for the same reason; long-duration nominal bonds get crushed in high-inflation years, which is why Treasury Inflation-Protected Securities (TIPS) exist as a separate product.

A few things to keep in mind

Match the time periods. A monthly return paired with an annual inflation figure produces a number that doesn't mean anything.

The real return here is pre-tax. In a taxable account, your after-tax real return is the one that drives long-term wealth, so it's worth running the numbers again with your effective tax rate.

The CPI doesn't necessarily match your inflation. If most of your spending goes to housing and healthcare, your personal cost of living can run hotter than the headline figure suggests.

When the nominal return is lower than inflation, the real return goes negative. That's not a math quirk; it means you lost ground in purchasing power even if the account balance went up.

Frequently asked questions

Why not just subtract inflation from the nominal return?

You can, and at small rates the answer is close. 10% minus 3% gives 7%; the Fisher equation gives 6.80%. At 15% with 10% inflation, the gap widens: subtraction says 5%, Fisher says 4.55%. The equation captures the compounding interaction between the two rates, and it matters more as the rates climb.

What counts as a good real return?

Stocks have delivered about 7% real annualized over a century of US history. Bonds land closer to 2 to 3% real. Cash usually sits near zero, sometimes negative. Anything positive means your wealth is growing; anything negative means inflation is winning.