Glossary
Comparison month
The later month in a CPI ratio, the level that gets divided by the base month.
The comparison month is the newer index level in the ratio. If the clause says 'the most recently published CPI as of sixty days before the anniversary,' the comparison month is whatever month was already published on that day, not the anniversary month itself.
Bimonthly metros do not have every month. Dallas-Fort Worth publishes odd months. Houston publishes even months. If the clause names a month that series does not print, you do not interpolate. You follow whatever substitute the clause itself names, and if it names none, the finding says the month is unpublished.
Using a comparison month from a different series than the base month invalidates the ratio. Both levels come from the same series ID.
Write the months on the worksheet as names and as the BLS period (2026-09), next to the index level to three decimals, so a reviewer can check the division without opening a second document.
Related terms
See it used in a worked example · CPI calculator · Request an audit
Sources and limits
Index levels from the U.S. Bureau of Labor Statistics Consumer Price Index, not seasonally adjusted, retrieved through the BLS Public Data API on November 1, 2026. Values are index points, not the headline 12-month percent.
Statewide rates reflect U.S. Department of Labor state minimum-wage postings as updated January 1, 2026, the U.S. Department of State Diplomatic Note on 2026 increases, and, for the prior-year comparison and named local rates, the National Employment Law Project compilation published in November 2025. Confirm the rate that applies to the workplace before using it in a bill.
The contracts in these worksheets are fictional. The prices are chosen so the arithmetic is easy to check. They are not a price survey and they are not client results.
RateClause is not a law firm. Nothing on this page is legal advice. Your clause controls, including whether a past period can be rebilled at all.
Primary postings: BLS Consumer Price Index, U.S. Department of Labor, state minimum wages, U.S. Department of State notice of 2026 minimum-wage increases.