How do I calculate the loss of purchasing power?
Divide the amount by (1 + inflation) raised to the number of years. At 3% for 10 years, €10,000 is equivalent to about €7,441 today, a loss of roughly 26%.
Inflation calculator
€10,000 ÷ (1 + 3 %)^20 − €10,000 = -€4,463
| Year | Cash (uninvested) | Index portfolio | Accumulated difference |
|---|---|---|---|
| 1 | €9,709 | €10,388 | €679 |
| 2 | €9,426 | €10,792 | €1,366 |
| 3 | €9,151 | €11,211 | €2,060 |
| 4 | €8,885 | €11,646 | €2,761 |
| 5 | €8,626 | €12,099 | €3,473 |
| 6 | €8,375 | €12,568 | €4,193 |
| 7 | €8,131 | €13,056 | €4,925 |
| 8 | €7,894 | €13,564 | €5,670 |
| 9 | €7,664 | €14,090 | €6,426 |
| 10 | €7,441 | €14,637 | €7,196 |
| 11 | €7,224 | €15,206 | €7,982 |
| 12 | €7,014 | €15,796 | €8,782 |
| 13 | €6,810 | €16,410 | €9,600 |
| 14 | €6,611 | €17,047 | €10,436 |
| 15 | €6,419 | €17,709 | €11,290 |
| 16 | €6,232 | €18,397 | €12,165 |
| 17 | €6,050 | €19,111 | €13,061 |
| 18 | €5,874 | €19,854 | €13,980 |
| 19 | €5,703 | €20,625 | €14,922 |
| 20 | €5,537 | €21,426 | €15,889 |
The real value of money is its nominal value divided by accumulated inflation: real value = amount ÷ (1 + inflation)^years. At a constant 3%, €1,000 kept for ten years buys what about €744 buys today, because 1.03^10 ≈ 1.344. The invested line applies the chosen return first and then the same deflator.
What matters for your purchasing power is the real return: (1 + nominal return) ÷ (1 + inflation) − 1. A 7% return with 3% inflation is about 3.9% in real terms, not 4%. A deposit paying less than inflation loses purchasing power even though the balance grows.
The European Central Bank targets 2% over the medium term, and euro-area inflation averaged somewhat below 2% between 1999 and 2020. It is not stable: in October 2022 it exceeded 10%. Try several rates to see a range instead of a single number. The rule of 70 gives a quick estimate: at 3% prices double in about 23 years.
Divide the amount by (1 + inflation) raised to the number of years. At 3% for 10 years, €10,000 is equivalent to about €7,441 today, a loss of roughly 26%.
It is the return after inflation: (1 + nominal return) ÷ (1 + inflation) − 1. It tells you how much more you can actually buy, not how many more euros you have.
No. It assumes a constant annual rate that you choose. Real inflation changes every year, so the result is an illustration of the mechanism, not a forecast.
No. The return is an assumption. Index portfolios have years with losses; a constant rate hides that volatility and does not include costs or taxes.