Prices rarely fall, so a dollar set aside in an earlier decade buys less today. This tool converts any amount between two years using the published Consumer Price Index, and reports the average annual inflation that got us from one to the other.
Any two years from 1913 to 2026, using annual averages of the CPI-U index.
Put the other way around: $100 in 2026 buys what $39.33 bought in 1990. Cash that earns less than 2.63% a year lost ground over this period.
Index used: U.S. Bureau of Labor Statistics — CPI-U, all items (series CPIAUCNS), annual averages. 2026 is a year-to-date average of the published months, not a completed year, so the most recent figure will shift slightly as the remaining months report. This is US inflation as measured; other countries price their baskets differently, and their central banks run separate targets.