How Inflation Works: Why Your Money Buys Less Over Time

A loaf of bread that cost one dollar in 1970 costs around four dollars today. That is not because bread became harder to make or wheat became rarer. It is because the dollar itself became worth less. Inflation is the name for that process: the general price level rising over time, which is another way of saying the purchasing power of money falling.

The tricky part is that inflation does not mean every price goes up by the same amount, at the same time, or even at all. Some prices fall even during periods of broad inflation. What matters is the average across a basket of goods and services. Statisticians track this with indices such as the Consumer Price Index, which samples thousands of prices from rent and petrol to haircuts and hospital visits, then weights them by how much households typically spend on each category.

The demand-pull mechanism

The most intuitive route to inflation is excess demand. When people collectively want to buy more than the economy can currently produce, sellers can raise prices without losing customers. They do, and the price level rises.

This can happen when consumer confidence is high and borrowing is cheap, so households spend freely. It can also happen when governments run large deficits and pump money into an economy through spending programmes. And it is one reason central banks pay close attention to employment: a very tight labour market typically means workers have more income to spend, which pushes demand upward.

The phrase “too much money chasing too few goods” captures this neatly. The goods and services are fixed in the short run; when the money supply expands faster than output, prices adjust upward to bring the two back into balance.

The cost-push mechanism

The second main route runs from the supply side. When the cost of producing things rises — energy prices spike, a key input becomes scarce, wages increase faster than productivity — producers face a choice: absorb the higher costs and accept lower profits, or pass them on through higher prices. In competitive markets they often do both partly. But sustained cost increases tend to show up in prices.

Oil price shocks are the textbook example. When crude becomes expensive, freight costs more, plastics cost more, heating costs more. The increase ripples through supply chains and arrives at the checkout as inflation in products that seem to have nothing to do with oil. This type of inflation is particularly awkward for policymakers because the usual tools — raising interest rates — can tame demand but do nothing to reduce the underlying cost shock.

Expectations and the wage-price spiral

There is a third mechanism that amplifies both of the above: expectations. If workers believe prices will rise five percent next year, they bargain for five percent higher wages now. If they succeed, firms face higher costs and raise prices to compensate — validating the expectation. Inflation becomes self-fulfilling.

This is why central banks place so much emphasis on credibility. If households and businesses genuinely believe the central bank will bring inflation back to target, expectations stay anchored and the spiral never starts. If credibility slips, the bank must inflict more economic pain — higher rates, slower growth, rising unemployment — to restore it.

Why central banks aim for low but positive inflation

Most central banks target inflation around two percent rather than zero. This seems counterintuitive: why not aim for prices that stay flat? The answer is that deflation — falling prices — is much more dangerous and far harder to escape.

When prices are expected to fall, consumers and businesses delay spending and investment: why buy today what will be cheaper next month? Spending drops, firms earn less, they lay off workers, demand falls further, and prices fall more. Japan spent decades trapped in this cycle after its asset bubble burst in the early 1990s. A small positive inflation buffer keeps the economy far from that edge.

Who gains and who loses

Inflation does not affect everyone equally. Borrowers with fixed-rate debt benefit: they repay in currency that has lost value, meaning the real burden of the debt shrinks. Savers holding cash lose purchasing power unless the interest rate on their savings exceeds inflation. Workers in sectors with strong unions can often negotiate wages that keep pace; those in weaker bargaining positions fall behind. Pensioners on fixed incomes are particularly exposed if their payments are not indexed to prices.

Governments that have large debts denominated in their own currency also benefit modestly from inflation: the real value of the debt falls. This is one reason that heavily indebted governments sometimes have an incentive to tolerate inflation that their central banks officially resist.