Investment Inflation Calculator
See what your investment is really worth: the exact real return after inflation (Fisher equation), a nominal-vs-real growth projector with annual contributions, and a purchasing-power time machine. Free, instant, 100% in your browser.
Real Return (Fisher Equation)
Enter a nominal return and an inflation rate. The calculator shows the exact real return — (1 + nominal) ÷ (1 + inflation) − 1 — alongside the popular nominal − inflation shortcut, so you can see how much the shortcut overstates reality.
Investment Growth Projector — Nominal vs Real
Project an investment forward with annual compounding, then strip out inflation to see the balance in today's dollars.
Nominal vs real balance
Year-by-year table
| Year | Contributed | Nominal balance | Real balance (today's $) |
|---|
Purchasing Power Projector
How much will today's money be worth in the future — and how much future money do you need to match today?
Methodology
- Real return (exact): Fisher equation — real = (1 + nominal) ÷ (1 + inflation) − 1. Example: 8% nominal, 3% inflation → (1.08 ÷ 1.03) − 1 = 4.8544%. The common shortcut nominal − inflation (= 5.0000%) overstates it by 0.1456 percentage points because it ignores compounding of inflation on the return itself.
- Nominal future value: FV = PV × (1 + n)t + PMT × (((1 + n)t − 1) ÷ n), with annual compounding and contributions added at year-end (n = 0 handled as simple accumulation).
- Real future value (today's dollars): nominal FV ÷ (1 + inflation)t. Example: 1.0820 = 4.66095714, so \$100,000 → \$466,095.71 nominally; 1.0320 = 1.80611123, so the real value is \$466,095.71 ÷ 1.80611123 = \$258,065.90.
- Purchasing power: future buying power = amount ÷ (1 + inflation)t; the future sum needed to match today = amount × (1 + inflation)t.
- Assumptions & limits: constant annual return, constant inflation, annual compounding, no taxes, no fees, no rebalancing. Real investing involves all of these, so treat every figure as an educational estimate, not financial advice.
Frequently asked questions
What is the real return on an investment?
The real return is your investment return after removing inflation, calculated exactly with the Fisher equation: real return = (1 + nominal) / (1 + inflation) - 1. For example, an 8% nominal return with 3% inflation gives (1.08 / 1.03) - 1 = 4.8544% real return. The shortcut of subtracting (8% - 3% = 5.0000%) overstates it by 0.1456 percentage points. The real return tells you how much richer you actually got in purchasing power.
How do I calculate my investment's value after inflation?
Project the nominal future value, then deflate it by inflation: real value = nominal value / (1 + inflation)^years. Example: $100,000 invested at 8% nominal for 20 years grows to $466,095.71 nominally, but with 3% annual inflation that is only $258,065.90 in today's dollars — inflation erodes 44.63% of the purchasing power. Use the Growth Projector tab above to run your own numbers.
What is $10,000 at 7% for 30 years really worth after inflation?
At 7% nominal for 30 years, $10,000 compounds to $76,122.55 nominally (1.07^30 = 7.61225504). With 3% annual inflation, that future sum buys only $31,361.48 in today's dollars. The gap — $44,761.07 — is the silent cost of inflation, and the exact real return behind it is (1.07 / 1.03) - 1 = 3.8835% per year.
Why is the exact real return different from nominal minus inflation?
Subtraction ignores compounding: inflation also eats the part of your return that came from growth on growth. The exact Fisher formula divides instead: (1 + n) / (1 + i) - 1. At 8% nominal and 3% inflation the exact real return is 4.8544%, while the shortcut says 5.0000% — a 0.1456 percentage-point overstatement. The error grows with bigger numbers: it matters for long horizons and high-inflation scenarios.
Can real return be negative?
Yes. Whenever inflation exceeds your nominal return, your purchasing power shrinks even as the balance grows. Example: a 3% nominal return with 5% inflation gives (1.03 / 1.05) - 1 = -1.9048% real per year — after 20 years you have more dollars but they buy less. Conversely, during deflation the exact real return exceeds the nominal rate: 5% nominal with -1% inflation gives (1.05 / 0.99) - 1 = 6.0606% real.
How much will I need in the future to match today's money?
Multiply today's amount by (1 + inflation)^years. To match $1,000,000 of today's purchasing power after 20 years of 4% inflation, you need $1,000,000 x 1.04^20 = $2,191,123.14. Flipped around, $1,000,000 received 20 years from now is worth only $456,386.95 in today's dollars. The Purchasing Power tab above computes both directions.
Do yearly contributions change the real return?
No — the annualized real return is the same Fisher result regardless of contributions, but contributions change the dollar outcome a lot. Example: $50,000 initial plus $6,000 per year for 25 years at 6% nominal grows to $543,780.61 nominally from $200,000 of total contributions (a $343,780.61 gain). In today's dollars at 3% inflation that is $259,712.65 — still a gain, but inflation claims nearly half the nominal result.
Is this calculator financial advice?
No. This is an educational estimate, not financial advice. It assumes a constant annual return and constant inflation, which never happens in reality — markets fluctuate, inflation varies, and taxes and fees also reduce returns. Do not make investment decisions based on these projections alone; consult a qualified financial professional for advice about your situation.
Sources & further reading
- Fisher, I. (1930). The Theory of Interest — the exact real-interest identity (1+i) = (1+r)(1+π).
- U.S. Bureau of Labor Statistics — Consumer Price Index (CPI) historical inflation data.
- Federal Reserve Bank of Minneapolis — CPI inflation calculator (long-run U.S. inflation reference).
Not financial advice. Figures on this page are mathematical estimates for education. Markets move, inflation shifts, and your actual taxes, fees, and timing will differ. Consult a qualified financial professional before acting.
Free tool by NRTechStudio