Real investment returns after inflation

Real vs Nominal Returns

Your nominal return is the percentage shown on your brokerage statement. Your real return is what's left after subtracting inflation. At 8% nominal return and 3% inflation, your real return is only ~4.85% (not simply 5%).

The Fisher Equation

Real Rate ≈ Nominal Rate − Inflation Rate. More precisely: (1 + real) = (1 + nominal)/(1 + inflation).

Why This Gap Matters More Over Time

Here is something many people overlook: the difference between nominal and real returns feels small in year one. Over decades, though, it compounds into something significant. A pot that looks impressive on paper can represent far less purchasing power than expected. It can help to think of inflation not as a one-off fee, but as a quiet annual charge on your future wealth. The longer your time horizon, the more this is worth considering when forming any long-term financial picture.

Common Mistakes People Make

One of the most frequent errors is planning purely around nominal figures. Seeing a projected balance double over twenty years feels encouraging. But if inflation has been running at 3% throughout, that figure buys considerably less than it appears. Another thing people miss is that inflation rates change. Using a single fixed rate is a simplification — which is exactly what this tool is designed. Treat the results as illustrations rather than precise forecasts, and explore a range of inflation assumptions to get a fuller sense of the picture.

Quick example

With investment amount of 10,000 and nominal annual return of 8 (plus annual inflation of 3 and years of 20), the result is 25,806.59. Change any figure and watch the output shift — it's often more useful to see the pattern than to memorise the formula.

Which inputs matter most

You enter Investment Amount, Nominal Annual Return, Annual Inflation, and Years. The rate and the time horizon usually dominate — compounding means a small change in either reshapes the final figure more than a similar shift in contribution size. Test this by doubling one input at a time.

What's happening under the hood

This calculator applies the Fisher equation to adjust nominal investment returns for inflation's eroding effect. It compounds the initial investment at the nominal rate, then divides by inflation compounding to show real purchasing power. Results assume constant annual rates with no fees or taxes—actual outcomes may vary based on market conditions and individual circumstances. The formula is listed in full below. If the number looks off, you can retrace the calculation by hand — that's the point of showing the working.

Why investors run this

Most people's intuition for compounding is wrong — not because the math is hard, but because linear thinking doesn't account for curves. Running numbers through a calculator like this one is the cheapest way to recalibrate that intuition before making an irreversible decision about contribution rate, asset mix, or retirement age.

What this doesn't capture

Steady-rate math ignores real-world volatility. Actual returns are lumpy; sequence-of-returns risk matters most in drawdown; fees and taxes drag on compound growth; and behaviour changes in drawdowns can reduce outcomes below the projection. Treat the number as one scenario, not a forecast.