Calculate Inflation-Adjusted Value

What Is Inflation?

Inflation is the rate at which the general level of prices for goods and services rises. As prices rise, each dollar you hold buys less. This tool shows the real numbers: if you had $100 in 1970, how much money would you need today to buy the same basket of goods and services, based on the official Consumer Price Index published by the U.S. Bureau of Labor Statistics.

How This Calculator Works

This tool uses the official monthly CPI-U All Items U.S. City Average series (CUUR0000SA0, based 1982–84 = 100) published by the BLS, covering every month from January 1913 through the most recent available release. The adjusted value is computed as Amount x (CPIend / CPIstart). Every index value used is shown in the results table, so the math is fully transparent and verifiable against the BLS.

Adjusted = Amount × (CPIend / CPIstart)

The average annual rate uses the compound annual growth rate formula (CAGR) across the exact number of months between the two dates, not an approximation.

Why AI Cannot Replace This Tool

Large language models routinely hallucinate historical prices and CPI index numbers, and they give different answers each time you ask. They cannot reliably recall the exact official CPI-U index for a specific month like March 1980 or May 2025. This tool uses the actual downloaded BLS CPI dataset with bit-exact deterministic arithmetic. You get the same precise, verifiable answer every single time, and you can see every index value used. That is accuracy an LLM conversation cannot provide.

Frequently Asked Questions

What is CPI-U?

CPI-U is the Consumer Price Index for All Urban Consumers, the headline inflation measure published monthly by the U.S. Bureau of Labor Statistics. It tracks the average price change of a fixed market basket of goods and services for all urban households. The U.S. city average, all items, not seasonally adjusted series is the standard reference used for inflation adjustment.

What does "inflation-adjusted value" mean?

It is how many dollars you would need at the end date to have the same purchasing power as your amount had at the start date. For example, if prices doubled between the start and end, $100 at the start would be worth the same as $200 at the end. The tool shows this dollar answer, the total percentage change, and the compound annual rate.

How is the average annual rate calculated?

It is the compound annual growth rate (CAGR) of prices between the two selected months: (CPIend/CPIstart)^(12 / months) - 1. This gives the equivalent constant yearly inflation rate over the whole period, so you can compare it to today's headline inflation number.

What does "purchasing power lost" mean?

It shows how much of the start value's buying power was lost to inflation by the end date. A 'purchasing power lost' of 50% means your money buys half as much as it did at the start (because prices doubled). If deflation occurred, this number is negative, meaning purchasing power increased.

Is this data current?

The dataset is the latest monthly CPI-U release available and is updated whenever the BLS publishes a new month. Using the latest release means your end month options always reflect the most recent official index values.

Does this tool work for other countries?

This tool is built around the U.S. CPI-U index. Other countries publish their own consumer price indices with different base periods, so the numbers here apply to U.S. dollars and U.S. prices only. For rough intuition, global inflation is often broadly similar, but exact figures differ by country.

Does this calculator save my data?

No. The calculation runs entirely in your browser. The historical CPI dataset is embedded locally in the page and your inputs never leave your device. Nothing is stored, tracked, or transmitted. It is 100% private.