Consumer Price Index (CPI) is the primary measure of inflation, often referred to simply as the “inflation index.” It tracks changes in retail prices for a government-defined basket of essential consumer goods and services.
How CPI Is Calculated (Formula)
In the United States, the CPI is calculated using price data for 265 goods and services across 85 cities. In Russia, the official “consumer basket” is defined by Federal Law No. 44-FZ “On the Consumer Basket for the Russian Federation,” which includes food, non-food items, and various services.
In general terms, the CPI is calculated as the ratio of the current-period cost of the fixed base-year basket to the base-year cost of that same basket.
The resulting CPI reflects changes in the cost of living. If Q0 represents the fixed quantities in the basket, and P0 and Pt are base-year and current prices respectively, the formula is:
CPI = ∑(Q0 × Pt) ÷ ∑(Q0 × P0) × 100%
The result is expressed as a percentage. A value above 100 indicates inflation — rising prices across the basket.
Why CPI Matters to Forex Traders
CPI is a key macroeconomic indicator, capturing inflation from the consumer’s perspective. Central banks closely monitor CPI data when setting interest rates. Traders use CPI reports to anticipate potential rate hikes or cuts — which directly influence currency strength and volatility.
Where to Find Official CPI Reports
CPI in the United States
- Source: Bureau of Labor Statistics, U.S. Department of Labor;
- Website: www.bls.gov/cpi
- Significance: High
CPI in the Eurozone
- Source: Eurostat;
- Website: http://ec.europa.eu/eurostat
- Significance: High.
CPI in Russia (Rosstat)
- Source: Federal State Statistics Service (Rosstat);
- Website: http://www.gks.ru
- Significance: High.
FAQ
What does CPI stand for?
CPI stands for Consumer Price Index — a weighted average of prices for a fixed basket of goods and services purchased by households.
How often is CPI released?
In the US: monthly (around the 10th–15th). In the Eurozone and Russia: monthly, with exact dates published in advance by respective statistical agencies.
Why does CPI affect currency values?
Higher-than-expected CPI may signal upcoming interest rate hikes, boosting demand for the currency; lower CPI can prompt rate cuts, weakening the currency.
