What is inflation?

Inflation is the rate at which the general level of prices rises across an economy. It is not the price of any one thing going up — petrol this month, bread the next — but the average movement of many prices together. Statisticians track this by pricing a fixed basket of goods and services repeatedly over time and following how the total cost of that basket changes. The result is a single number, usually called the consumer price index, and its rate of change is the inflation rate.

Prices up is money down

“Prices are rising” and “money is losing value” describe the same fact from two directions. If a basket of goods that cost €100 last year costs €105 this year, then the same €100 buys less than it used to — it now buys only what roughly €95.24 would have bought a year earlier. There is no version of rising prices that does not also mean falling purchasing power. People tend to notice the first description, because price tags are visible and money in a wallet or account looks unchanged. The second description is the one that actually matters for saving, borrowing and spending decisions, because it tells you what your money can do, not just what it says on the label.

How it is measured

The basic idea is simple: pick a basket of goods and services that a typical household buys — food, housing, transport, healthcare, and so on — and price that exact basket at regular intervals. Because the basket is fixed, any change in its total cost reflects price movement rather than people buying different things. National statistics offices carry out this pricing exercise on a large scale, collecting many thousands of individual prices and weighting them according to how much of a typical budget each category represents.

Baskets are not frozen forever. Spending patterns shift — new products appear, old ones fade, and the share of income going to different categories changes — so statisticians periodically update what is in the basket and how heavily each item is weighted. What emerges from all this collection and weighting is a single figure, the consumer price index, which compresses millions of individual price observations into one number that can be compared across months and years.

Why it compounds

Inflation does not simply add up year after year — it compounds, because each year’s price rise applies to prices that are already higher than they were originally. A rise of 2% this year is calculated on top of last year’s already-inflated prices, not on the original starting point. Over enough years this compounding adds up to more than casual multiplication would suggest.

At a steady 2% a year, something costing €100 today costs €121.90 in ten years. At a steady 10% a year, the same starting basket reaches €259.37 in ten years — more than double, because 10% compounded is far more punishing than 10% simply multiplied by ten years. This is the same mechanical process as compound interest, just working in the direction of prices rather than savings.

What causes it

There is no single, agreed cause of inflation — economists generally group the drivers into three broad categories. Demand pressures arise when spending in an economy outpaces the supply of goods and services available to meet it. Cost pressures arise when the inputs businesses rely on — wages, energy, raw materials — become more expensive, and firms pass some of that cost on in higher prices. Expectations matter too: if people and businesses expect prices to keep rising, that expectation can shape wage demands and pricing decisions in ways that help make the rise happen. Most real episodes of inflation involve some mix of all three, and economists disagree about how much weight each deserves in any given period.

Many central banks aim for a low, steady inflation rate — often cited as around 2% — rather than zero. Central banks generally, and the European Central Bank in its published explainer, give similar reasoning: a small positive inflation target creates a buffer against deflation, which is harder to escape and more damaging once it takes hold, and it leaves room for individual prices to adjust up or down relative to one another even while the overall average stays low and stable.

Around does not yet report live inflation data, so no current-year figure is given here; treat the rates used in this guide’s examples as illustrations of the mechanism, not a forecast or a live reading.

Living with it

The question that matters is never “will prices rise” — over any meaningful stretch of time, they almost always do. The question is whether your money is growing faster or slower than prices are rising. A savings account paying 5% while inflation runs at 2% is growing your purchasing power at a real rate of about 2.94% a year. A return of 10% alongside 8% inflation leaves you with a real rate of roughly 1.85% a year — noticeably less than the crude “just subtract” shortcut of 2% would suggest, because the two effects compound against each other rather than simply cancelling. And a return of only 2% against inflation of 5% turns negative in real terms: about -2.86% a year, meaning the saver loses purchasing power even while their account balance keeps rising.

The same arithmetic applies to anything paid out in the future. A payment of €10,000 promised in 30 years is worth only about €5,520.71 in today’s purchasing power if prices rise at 2% a year throughout. A sum of €26,533 arriving in 20 years buys around €17,856 of what today’s money buys, under the same assumption. None of this is a reason to avoid saving or to distrust future payments — it is simply the reason “how much” is never a complete answer on its own. “How much, and growing at what real rate” is the fuller question, and it is the one worth asking of every return, salary, pension or contract you meet.