Inflation Adjustment Calculator

Illustrative example (hypothetical figures). This page holds no CPI data, so the two index values below are made-up round numbers, not real CPI readings. For a real adjustment, take both from the U.S. Bureau of Labor Statistics series listed under Methodology (Consumer Price Index — databases and series). Entered into the calculator:

• Amount to adjust: $40,000
• CPI at the starting period: 100 (hypothetical)
• CPI at the ending period: 125 (hypothetical)
• Years between the periods: 8

The calculator returns:

• Equivalent amount: $50,000.00
• Cumulative price change: 25.00%
• Average annual rate: 2.829%, compounded
• Held as cash, worth: $32,000.00 in starting-period dollars

In plain English: $40,000.00 in the starting period has the same purchasing power as $50,000.00 in the ending period. Run the other way, $40,000 held as cash across the same eight years buys only what $32,000 bought at the start, 20.00% less purchasing power. The 2.829% is the steady yearly rate that compounds to the 25% total over eight years.

Use the index value, not the inflation rate. CPI is published as an index level — a number in the hundreds — and the ratio between two levels is what converts dollars. Entering a percentage change in those fields produces a confident, meaningless answer.

Take both figures from the same series. Seasonally adjusted and unadjusted CPI values are both correct and are not interchangeable; mixing one of each introduces an error the arithmetic cannot see and the result will not reveal. The same applies to mixing a regional series with the national one.

Record which series and which periods you used. The reason this page asks for optional period labels is that they travel into the worked solution, so the calculation you paste into a document carries its own provenance instead of arriving as a bare number.

The arithmetic here is the standard CPI ratio method used to restate dollar amounts across periods. What is deliberate is what the page does not contain: any CPI data. Both index values are inputs, sourced by you from the live BLS series and optionally labelled with their own periods.

That choice costs a little convenience and buys the thing that matters on a site whose promise is verification. An embedded price table cannot stay correct — BLS publishes monthly and revises seasonally adjusted series afterwards — so a copied table drifts silently while continuing to look authoritative. A calculator that quietly rots is worse than one that asks you for a citation, because only one of the two fails visibly.

All arithmetic runs in your browser; nothing you enter is transmitted or stored. The sources below link to the agency documents themselves, so you are always reading the current figure rather than a copy of it.