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Inflation

Inflation changes the purchasing power of money, redistributes gains and losses across borrowers, lenders, workers and firms, and strongly influences monetary policy and financial-market expectations.

Entry type: Knowledge article

Field: Macroeconomics

Last reviewed: 24 August 2026

Definition

Inflation is a sustained increase in the general price level of goods and services, usually expressed as the percentage change in a broad price index over a specified period.

Measurement

Consumer price indices measure the changing cost of a representative consumption basket, while GDP deflators cover domestically produced final goods and services. Headline inflation includes all measured items; core measures exclude or statistically reduce volatile components to help identify persistent price pressure. Every measure depends on weights, quality adjustments, substitution assumptions and the population represented.

Drivers

Demand

  • Household and business spending
  • Fiscal stimulus
  • Credit and financial conditions

Supply and costs

  • Energy and commodity shocks
  • Wages and productivity
  • Supply-chain constraints

Expectations and institutions

  • Price- and wage-setting behaviour
  • Exchange-rate movements
  • Policy credibility

Economic effects

ChannelEffectDistributional issue
Purchasing powerNominal income buys fewer goods and servicesLosses are larger when wages or benefits adjust slowly
DebtUnexpected inflation reduces the real value of fixed nominal liabilitiesBorrowers may gain at lenders' expense
Interest ratesExpected inflation is reflected in nominal yieldsCash and fixed-rate assets face differing exposures
PlanningPrice uncertainty complicates contracts and investmentFirms with pricing power adjust more easily

Important distinctions

Disinflation means inflation remains positive but slows; deflation means the general price level falls. A one-time price-level increase is not continuing inflation unless subsequent prices keep rising. Relative-price changes redistribute demand between products, whereas inflation describes a broad movement. Expected and unexpected inflation can produce very different contractual and distributional consequences.

Sources and further reading

View sources and editorial notes
  • International Monetary Fund, inflation and monetary-policy resources.
  • Bank for International Settlements, research on inflation dynamics.
  • OECD, consumer price indices and methodological guidance.

Editorial note: Inflation experiences vary across households and businesses because their spending baskets, incomes, debts and pricing power differ. This entry is informational and does not provide economic or investment advice.