Inflation measures how quickly prices are rising across an economy. It's arguably the single most important economic data series for currency traders, because most central banks have an explicit mandate to control it, and their policy response directly moves interest rates.
What CPI Measures
The Consumer Price Index tracks the price of a representative basket of goods and services — housing, food, transport, healthcare, and more — bought by typical households. It's usually reported both month-over-month and year-over-year.
Headline vs. Core
Headline CPI includes everything, including food and energy prices, which can swing sharply due to short-term supply shocks unrelated to underlying demand. Core CPI strips those out to reveal the more persistent inflation trend that central banks tend to focus on when setting policy.
| Measure | Includes food/energy? | Best for |
|---|---|---|
| Headline CPI | Yes | Cost-of-living perception |
| Core CPI | No | Central bank policy decisions |
What PPI Measures
The Producer Price Index tracks price changes at the wholesale level — what producers receive for goods before they reach consumers. Because cost pressures at the producer level often filter through to consumer prices later, PPI is sometimes viewed as a leading signal for future CPI trends.
Why Inflation Data Moves Currencies
Inflation surprises change expectations for the central bank's next move. Hotter-than-expected inflation increases the odds of tighter policy (or reduces the odds of easing), which tends to support the currency. Cooler-than-expected inflation works the other way.
A CPI print of 3% can send a currency higher or lower depending entirely on whether the market expected 2.8% or 3.4%. Always check consensus forecasts before the release, and read the reaction relative to that number, not the headline figure alone.
Other Inflation Gauges Worth Knowing
- ▸PCE (Personal Consumption Expenditures) — the Fed's preferred inflation gauge in the US.
- ▸HICP (Harmonised Index of Consumer Prices) — the ECB's standard measure across the eurozone.
- ▸Wage growth data — often watched alongside inflation as a sign of persistent price pressure.
Practical Reading Checklist
- 1.Check the consensus forecast before the release.
- 2.Compare both headline and core figures to expectations.
- 3.Read the month-over-month figure for momentum, year-over-year for the broader trend.
- 4.Consider how the print changes the odds of the next central bank move.