Glossary
Consumer Price Index (CPI)
Short answer
The Consumer Price Index (CPI) is a measure of the average change over time in prices paid by consumers for a basket of goods and services. In the United States it is published by the Bureau of Labor Statistics and is widely used in contracts to adjust prices for inflation.
By Pactinel editorial teamReviewed on October 22, 2026
In US contracts, "CPI" usually means the Consumer Price Index for All Urban Consumers (CPI-U) published monthly by the Bureau of Labor Statistics (BLS). Other countries publish their own consumer price indices, and some use the name CPI as well, including the UK (CPI), so the clause must say which one.
What a clause must specify
- The exact series (for example, CPI-U, U.S. city average, all items).
- Seasonally adjusted or not. Contracts normally use not seasonally adjusted figures.
- The base month and the comparison month.
- A fallback if the BLS changes or stops publishing the series.
Example clause
"Fees increase on each anniversary by the percentage increase in the CPI-U (U.S. city average, all items, not seasonally adjusted) between the month three months before the previous adjustment and the month three months before the current adjustment."
A lag of a few months is common because figures are published after the month ends.
Related indices
Euro area contracts often use HICP; UK contracts may use CPI or RPI. In Turkey, TÜFE, the consumer price index published by TÜİK, is the usual reference.
See indexation for the calculation.
This is general information, not legal advice.