How Inflation Erodes Purchasing Power
Inflation is the rate at which prices rise over time. As prices increase, each unit of currency buys fewer goods and services. A basket of groceries that cost €100 in 2010 costs significantly more today — not because the food changed, but because the money is worth less.
Understanding inflation is essential for any long-term financial decision. Savings, pensions, salary negotiations, investment returns, and debt all need to be evaluated in real terms — after inflation — to give a meaningful picture.
The Formula
Future Value = Present Value × (1 + inflation rate)^years
Past Value = Present Value ÷ (1 + inflation rate)^years
Purchasing Power Lost = Original Amount − Adjusted Value
Compound inflation means the effect accelerates over time. A small annual rate creates a large cumulative impact over decades.
Why Low Inflation Still Matters
At 2% annual inflation, a sum of money loses roughly 18% of its purchasing power over 10 years and over 45% over 30 years. This is why keeping large amounts in cash for long periods is a financial risk. The number does not change, but what it can buy does.
Inflation and Your Savings Rate
If your savings account earns 1.5% interest and inflation is 2.5%, your real return is -1%. You are losing purchasing power even though your balance is growing. The real return is always the nominal return minus inflation.
Frequently Asked Questions
What inflation rate should I use?+
For recent periods, use your country's official average from the relevant years. Central bank targets are typically 2%. For long-term projections, 2% to 3% is a commonly used assumption. The calculator pre-fills a reasonable default based on your country selection, but you can override it.
How is inflation measured?+
Inflation is typically measured using a Consumer Price Index (CPI), which tracks price changes across a standardised basket of goods and services. Different countries use slightly different baskets and methodologies, which is why rates vary even within the Eurozone.
Does this calculator use real historical rates?+
This calculator uses a single average annual rate that you enter or that is pre-filled based on country selection. It does not pull year-by-year historical CPI data. For the most precise historical adjustment, use your national statistics office data (CBS for Netherlands, ONS for UK, BLS for US).
What is the difference between inflation and purchasing power?+
Inflation is the rate of price increase. Purchasing power is what a given amount of money can actually buy. They are inversely related — when inflation rises, purchasing power falls. This calculator shows both: the inflation-adjusted value and how much purchasing power was lost.
How does inflation affect long-term savings?+
Inflation is the primary reason that holding cash for decades is financially costly. A pension fund, savings pot, or investment portfolio must generate returns above the inflation rate just to maintain real value. Returns below inflation mean you are losing ground in real terms, even if the nominal balance grows.