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Cost of inaction simulator: what inflation takes from your savings
Savings that earn less than inflation lose value every year, even when the balance goes up. With 2% inflation, €100,000 left for ten years in an account paying 1% is worth only about €90,700 in today's purchasing power.
What your savings will be worth in today's purchasing power
Inflation, current return and comparison return, all adjustable
The widening gap between the two trajectories
The simulator
Put a figure on the cost of idle savings
Enter your savings, your monthly contribution, your horizon, the inflation rate you assume and the two returns to compare. The calculation runs in your browser: your data is neither stored nor transmitted.
Cost of inaction simulator
Measure what your savings will really be worth in today's purchasing power, and the gap with the return you set.
Indicative calculation, based on 2026 rules and the assumptions entered above.
Why
Why a rising balance can hide a loss
An account balance does not measure what the money can buy. When the return on savings stays below inflation, its purchasing power falls, even if the figure shown rises every year.
Regulated savings accounts are exempt from income tax and social charges, but capped (€22,950 for the Livret A, €12,000 for the LDDS) and pay a rate set by the State; a current account earns nothing. Beyond precautionary savings, money left there pays the price of inflation every year.
The simulator does not tell you where to invest: it measures the cost of not deciding, using the assumptions you set.
What the calculation shows
What the calculation reveals
At 2% a year, prices rise by 22% in 10 years and by 49% in 20 years. Capital that does not grow at the same pace loses the difference every year, and the loss grows over time.
Three to six months of expenses is enough to deal with the unexpected. Beyond that, idle money is no longer a safety net: it is a cost, which the simulator puts a figure on in today's euros.
The simulator promises no return: it compares two trajectories using the rates you enter. It is the gap between them, not the absolute figure, that measures the price of waiting.
Case study
Case study: €150,000 of personal cash in a current account
An executive leaves €150,000 in his current account for 10 years, with no further payments, with inflation at 2% a year.
| Assumption | Balance in 10 years | Today's purchasing power |
|---|---|---|
| Current account, 0% | €150,000 | €123,052 |
| Investment at 3% a year | €202,403 | €166,041 |
| Investment at 4% a year | €223,625 | €183,450 |
Monthly compounding, before tax; purchasing power calculated with 2% inflation a year.
In the current account, he loses nearly €27,000 of purchasing power without seeing his balance fall. Invested at 3%, the same capital is worth €43,000 more in today's euros: that is the cost of ten years of waiting.
In practice
Measure before deciding
This simulator puts a figure on a cost that the bank statement does not show. What comes next — how much to keep available, how much to invest, in which wrapper and over what horizon — depends on your full situation: that is the purpose of a wealth review, at a fixed price stated before any commitment.
Frequently asked questions
What clients ask us.
What inflation rate should I use?
The European Central Bank's target is 2% a year over the medium term: this is the default assumption. Also test 3% to measure how sensitive your savings are.
Does the calculation take taxes into account?
No. Regulated savings accounts are exempt; other investments bear the income tax and social charges of their wrapper — 17.2% on assurance-vie, 18.6% on interest and capital gains in a securities account in 2026. The simulator compares two trajectories before tax.
How much should I keep available?
As a rule, three to six months of expenses. The Livret A is capped at €22,950 and the LDDS at €12,000: beyond that, precautionary savings belong elsewhere.
