How to compare prices across years (and what the CPI is)
A price from 1980 and a price from today aren't measured in the same "dollar". Inflation slowly shrinks what a dollar buys, so to compare them fairly you first turn the old price into today's money. Every page on this site does that with the consumer price index, or CPI.
What the CPI is
The consumer price index is published every month by the US Bureau of Labor Statistics (BLS). BLS staff record the prices of a large, fixed "basket" of goods and services that city households buy, from food and rent to doctor visits and car insurance, in cities across the country. The index shows how the cost of that basket changes over time. We use the most common version, called CPI-U (all urban consumers, all items, US city average), as a yearly average.
The CPI is set so that its average over 1982 to 1984 equals 100. In 1980 it averaged 82.4; in 2025 it averaged 321.9. That means the basket cost about 3.9 times as much in 2025 as in 1980.
Turning an old price into today's money
The sum is simple: old price × (CPI today ÷ CPI back then).
Take a first-class stamp. In 1980 it cost $0.15. Multiply by 321.9 ÷ 82.4 and you get about $0.59 in 2025 money. A stamp costs $0.82 in 2026, so stamps rose faster than prices in general. See the stamp's price history.
Eggs are a different story. A dozen cost $0.84 in 1980, which is about $3.28 in 2025 money, and $4.25 in 2025. See the egg price history.
What "real" prices tell you
When an item's price grows faster than the CPI, it takes a bigger bite out of a typical budget than it used to; we say its "real" price rose. When it grows slower, its real price fell, even if the number on the price tag went up. That's how something can cost more dollars than in 1980 and still be cheaper.
Things to keep in mind
- Averages hide differences. The CPI and the prices on this site are US averages. Prices in New York or rural Kansas can be quite different.
- Products change. A new car or a plane ticket today isn't quite the same thing as in 1980. BLS adjusts its index for some quality changes; the item prices on this site are as published.
- Pay matters too. Whether something feels expensive also depends on income. Compare with average hourly pay or household income.
- The latest year. We use yearly CPI averages, so comparisons run to 2025, the latest full year published. A few items have a newer price (such as this year's stamp rate); their comparison still stops at 2025.
CPI figures: US Bureau of Labor Statistics, CPI-U yearly averages, as published by the Federal Reserve Bank of Minneapolis. View the source.