Real Return After Inflation (Calculator & Formula Explained)
Simulator — Real return after inflation
Measure the impact of inflation on your returns. See also: Inflation and investing.
Real return measures the actual performance of an investment once inflation has been deducted. It is this figure — not the nominal return shown on the statement — that reflects the real change in the purchasing power of your savings. A Livret A paying 3% in an environment with 2.5% inflation produces only a 0.5% real return. An investment earning 5% with 5% inflation creates no additional wealth. Understanding this distinction is a prerequisite for any serious financial analysis.
The real return formula (Fisher equation)
The calculation of real return is based on the Fisher equation, named after economist Irving Fisher. Unlike the common approximation of simply subtracting inflation from nominal return, this formula accounts for the multiplicative effect:
(1 + rreal) = (1 + rnominal) / (1 + i)
So, isolating real return:
rreal = (1 + rnominal) / (1 + i) − 1
Where:
- rreal = real return (adjusted for inflation)
- rnominal = nominal return (the rate shown by the investment)
- i = inflation rate over the same period
The simplified approximation rreal ≈ rnominal − i is acceptable when rates are low (below 5%). Beyond that, the gap between the approximation and the exact formula becomes significant.
Concrete example: an investment returning 6% with 3% inflation
Let’s take an investment with a nominal annual return of 6% in an environment where inflation is 3%.
Simple approximation: 6% − 3% = 3% real return.
Fisher formula: (1.06 / 1.03) − 1 = 0.0291, or 2.91% real return.
The difference may seem modest — 0.09 percentage point — but it widens over time and with higher rates. On a capital base of €100,000 invested for 20 years, this gap represents a difference in purchasing power of several thousand euros.
Apply the same calculation to a common scenario: a Livret A paying 3% with 2.5% inflation. The real return is (1.03 / 1.025) − 1 = 0.49%. The Livret A barely preserves purchasing power in this environment.
Table: real return by nominal return and inflation rate
This table cross-references different levels of nominal return and inflation to show the corresponding real return (Fisher equation).
| Nominal Inflation | 1% | 2% | 3% | 4% | 5% |
|---|---|---|---|---|---|
| 2% | 0.99% | 0.00% | −0.97% | −1.92% | −2.86% |
| 3% | 1.98% | 0.98% | 0.00% | −0.96% | −1.90% |
| 5% | 3.96% | 2.94% | 1.94% | 0.96% | 0.00% |
| 7% | 5.94% | 4.90% | 3.88% | 2.88% | 1.90% |
| 10% | 8.91% | 7.84% | 6.80% | 5.77% | 4.76% |
The red cells indicate a negative real return: the investment loses purchasing power despite a positive nominal return. This is the case for any investment whose rate is below inflation — a common situation for regulated savings accounts and euro funds in life insurance policies during periods of rising prices.
Real return simulator after inflation
This simulator calculates the real return of any investment by applying the Fisher equation. It highlights the gap between the headline return and the effective return in purchasing-power terms, and projects the growth of capital over the selected time horizon.
The results provided by this simulator are purely indicative and educational. They do not constitute investment advice, a personalized recommendation, or an incentive to use a specific financial product.
This result directly informs two key decisions: should you repay debt or invest? Test it with the simulator for debt vs. savings arbitrage. And to assess whether your capital is sufficient to generate sustainable income, use the simulator for capital needed to live off your passive income.
The concrete impact of inflation on capital over time
Erosion of purchasing power through inflation is a gradual but cumulative phenomenon. A capital base of €100,000 that earns no return mechanically loses value each year in real terms.
| Duration | 2% inflation | 3% inflation | 5% inflation |
|---|---|---|---|
| 5 years | €90,573 | €86,261 | €78,353 |
| 10 years | €82,035 | €74,409 | €61,391 |
| 20 years | €67,297 | €55,368 | €37,689 |
| 30 years | €55,207 | €41,199 | €23,138 |
This table shows the real purchasing power of €100,000 left uninvested over different time horizons. With 3% inflation, capital that is not invested loses more than half of its purchasing power over 30 years. That is why real return — not nominal return — is the relevant metric for evaluating a long-term savings strategy.
Estimated real return by asset class
Real return varies widely by asset class. The following table provides historical order-of-magnitude estimates for illustrative purposes, using 2% inflation as the reference.
| Investment | Indicative nominal return | Real return (2% inflation) |
|---|---|---|
| Livret A | 3.0% | 0.98% |
| Euro funds in life insurance | 2.5% | 0.49% |
| Government bonds (10-year OAT) | 3.5% | 1.47% |
| Diversified equities (long term) | 7.0% | 4.90% |
| Rental real estate (gross) | 5.0% | 2.94% |
These returns are historical order-of-magnitude estimates and do not predict future performance. Net real return also depends on the tax treatment applicable to the wrapper used.
Real return and compound interest
Real return interacts directly with the mechanism of compound interest. When projecting capital growth over 10 or 20 years, using nominal return systematically overstates the result in purchasing-power terms.
To obtain a realistic projection, it is preferable to apply real return in compounding formulas. An investment showing 6% nominal return with 2% inflation produces real growth equivalent to a 3.92% investment with no inflation. Over 20 years and €50,000 of capital, the difference between the nominal projection (€160,357) and the real purchasing-power projection (€107,148) exceeds €53,000.
That is why our monthly savings goal calculators become even more useful when used together with this real return simulator.
Frequently asked questions about real return
What is the difference between nominal return and real return?
Nominal return is the rate shown by the investment, before any adjustment. Real return subtracts inflation to measure the actual change in purchasing power. An investment returning 4% nominal with 2% inflation produces a real return of about 1.96% (Fisher equation). Real return determines whether the saver is getting richer or poorer in purchasing-power terms.
How do you calculate the real return of an investment?
The exact formula is: rreal = (1 + rnominal) / (1 + inflation) − 1. For example, with a nominal return of 5% and inflation of 2%: (1.05 / 1.02) − 1 = 2.94%. The approximation rreal ≈ rnominal − inflation (i.e. 3%) is acceptable at low rates but becomes imprecise beyond 5%.
Does the Livret A protect against inflation?
The Livret A rate is partially indexed to inflation, but it does not fully offset inflation in every environment. With a rate of 3% and inflation of 2.5%, the real return is about 0.49%. The Livret A therefore preserves purchasing power only marginally, without meaningfully growing it. Its main advantage lies in liquidity and tax exemption, not in real return.
Why is the approximation (nominal − inflation) imprecise?
Because it ignores the interaction between the two rates. When you earn 10% on capital, inflation also applies to the interest earned, not just to the original principal. The Fisher equation captures this multiplicative effect. The gap is 0.09 percentage point for a 6%/3% pair, but rises to 0.45 point for a 10%/5% pair — which is significant over a long horizon.
What real return should you aim for to grow wealth?
A real return above 0% preserves purchasing power. A real return of 2% to 4% allows effective growth in wealth after inflation. Historically, diversified equities over the long term have delivered an average real return of 4% to 5% per year, but with significant volatility. Capital-guaranteed products typically offer a real return between 0% and 1%.
Key takeaways
- Real return is the only metric that measures the actual change in an investment’s purchasing power.
- The Fisher equation — rreal = (1 + rnominal) / (1 + inflation) − 1 — is more precise than simple subtraction, especially when rates exceed 5%.
- A positive nominal return can mask a real loss of purchasing power if inflation is higher than the investment rate.
- Over a long horizon, the gap between nominal projection and real purchasing-power projection can exceed several tens of thousands of euros.
- This simulator is an educational estimation tool. It does not constitute investment advice and does not replace personalized guidance.