How the inflation calculator works
Inflation means prices rise over time, so the same amount of money buys less. To compare money from two different years, you need a price index: a number that tracks the cost of a typical basket of goods and services. In the US, the standard measure is the Consumer Price Index for All Urban Consumers (CPI-U), published every month by the Bureau of Labor Statistics (BLS).
The calculator has two modes.
- US CPI data compares two years from 1913 to 2025 using official CPI-U annual averages, plus the latest monthly index for 2026.
- Your own rate projects forward with any inflation rate, in any currency. Use it for future planning or for countries other than the US.
Comparing two years
To restate an amount from one year in another year’s dollars, scale it by the ratio of the two index values.
The average yearly inflation between the two years is the compound rate that links the two index values.
Projecting forward
With a chosen rate r, a price grows by (1 + r) every year, and money held as cash loses buying power by the same factor.
Buying power = amount ÷ (1 + r)^years
Worked examples
What was $100 in 1990 worth in 2025? The CPI-U averaged 130.7 in 1990 and 321.943 in 2025. So 100 × 321.943 ÷ 130.7 = $246.32. Prices rose 146.3% in total, an average of about 2.6% a year over 35 years.
A $50,000 salary in 2000. In 2025 dollars that is 50,000 × 321.943 ÷ 172.2 = $93,479. If your pay went from $50,000 in 2000 to $85,000 in 2025, it rose on paper but fell by about 9% in real terms.
Planning ahead. At 3% inflation, something that costs $1,000 today would cost about $1,806 in 20 years. Put the other way, $1,000 kept under the mattress for 20 years would only buy what $554 buys today.
What $100 from past years is worth in 2025
These figures use CPI-U annual averages, so they show typical prices for each year as a whole.
| Year | CPI-U (annual average) | $100 then, in 2025 dollars | Average inflation per year since |
|---|---|---|---|
| 1950 | 24.1 | $1,335.86 | 3.5% |
| 1970 | 38.8 | $829.75 | 3.9% |
| 1980 | 82.4 | $390.71 | 3.1% |
| 1990 | 130.7 | $246.32 | 2.6% |
| 2000 | 172.2 | $186.96 | 2.5% |
| 2010 | 218.056 | $147.64 | 2.6% |
| 2020 | 258.811 | $124.39 | 4.5% |
The jump for 2020 stands out. Inflation reached 4.7% in 2021 and 8.0% in 2022, the highest since the early 1980s, so prices rose about 24% in just five years.
Things to know about CPI figures
- Annual averages vs single months. This tool uses yearly averages, which smooth out seasonal swings. The BLS CPI Inflation Calculator compares single months, so its answers can differ slightly.
- The latest month. Choosing the latest month (September 2026) uses that month’s index instead of an average, so it captures price changes so far this year.
- CPI is an average basket. Your own inflation depends on what you buy. Rent, healthcare, tuition and energy have often risen faster than the overall index, while many electronics have become cheaper.
- Deflation happens too. Prices fell in the early 1930s: the index dropped about 24% from 1929 to 1933. In 2009, average prices fell 0.4%. Going back to an earlier year from a later one is simply the formula in reverse.
- Missing month in 2025. The BLS did not publish an October 2025 index because of the lapse in federal funding. The 2025 annual average shown here is the one the BLS published.
How to use the result
Adjusting for inflation turns “nominal” money into “real” money, and that changes many decisions.
- Pay rises. A 3% raise in a year with 4% inflation is a real pay cut.
- Savings. Savings only grow in real terms if the interest rate beats inflation. Compare the two with the compound interest calculator, which has an inflation adjustment.
- Retirement. An income that feels large today will shrink over a 30-year retirement. The retirement calculator raises your withdrawals with inflation every year.
- Price changes. To see the percentage change between any two prices, use the percentage increase calculator.
A quick rule of thumb: divide 70 by the inflation rate to estimate how many years it takes for prices to double. At 3% a year, prices double in roughly 23 years. The Federal Reserve aims for inflation of 2% a year over the longer run, which halves the buying power of cash in about 35 years.