How to use the inflation calculator
On the U.S. CPI data tab, enter an amount and pick the two dates, either a full year or a single month from 1913 on. The calculator shows what the amount is worth at the other date, the total price change, the average yearly inflation and a year-by-year graph and table. The Future value and Past value tabs use one steady inflation rate that you choose, for years with no CPI yet or to test a scenario.
What is inflation?
Inflation is the rise in prices over time, so the same dollar buys less. In the United States it is measured by the Consumer Price Index for All Urban Consumers (CPI-U), which the Bureau of Labor Statistics publishes every month from the prices of a basket of goods and services. Prices have gone up in most years; in a few, such as the early 1920s and the Great Depression, they fell (deflation).
Inflation formula
An amount is converted with the ratio of the index in the two periods: value = amount × CPI at the second date ÷ CPI at the first date. A year uses the average of its monthly indexes. The average yearly inflation over the period is the compound rate: (CPI at the second date ÷ CPI at the first date)1 ÷ years − 1.
Inflation calculator example
The CPI-U averaged 10.108 in 1915 and 321.943 in 2025. So $10,000.00 in 1915 buys as much as $10,000.00 × 321.943 ÷ 10.108 = $318,492.66 in 2025. Prices rose 31.85 times over 110 years, an average of 3.20% a year.
What $100.00 from past years is worth in 2025
| Year | CPI-U | Worth in 2025 | Average inflation since |
|---|---|---|---|
| 1920 | 20.042 | $1,606.37 | 2.68% |
| 1930 | 16.700 | $1,927.80 | 3.16% |
| 1950 | 24.067 | $1,337.71 | 3.52% |
| 1970 | 38.825 | $829.22 | 3.92% |
| 1980 | 82.408 | $390.67 | 3.07% |
| 1990 | 130.658 | $246.40 | 2.61% |
| 2000 | 172.200 | $186.96 | 2.53% |
| 2010 | 218.056 | $147.64 | 2.63% |
| 2020 | 258.811 | $124.39 | 4.46% |
Future cost at a steady inflation rate
The flat rate calculators use future value = amount × (1 + rate)years, and the past value divides by the same factor. At 3% a year, $100.00 today will need to be $134.39 in 10 years, and prices double in about 23 years.
| Inflation | In 10 years | In 20 years | In 30 years |
|---|---|---|---|
| 2% a year | $121.90 | $148.59 | $181.14 |
| 3% a year | $134.39 | $180.61 | $242.73 |
| 4% a year | $148.02 | $219.11 | $324.34 |
| 5% a year | $162.89 | $265.33 | $432.19 |
What $100.00 of today's prices will cost.
Inflation in Excel
With the amount in A1 and the two CPI values in B1 and B2, =A1*B2/B1 gives the value at the second date and =(B2/B1)^(1/years)-1 the average yearly inflation. For a steady rate, =FV(3%,10,0,-100) returns $134.39.
About the data
- From 1913 on, the official CPI-U, U.S. city average, all items, not seasonally adjusted (1982-84 = 100).
- Before 1913, yearly estimates from historical price studies, joined to the official index. They are less precise.
- BLS did not publish a CPI for October 2025 because of the federal government shutdown, so the 2025 average uses 11 months.
- The latest month is September 2026; the 2026 average uses the 9 months published so far.
Related calculators
To see whether your savings beat inflation, compare their growth in the compound interest calculator or the savings calculator. The future value and present value calculators work with any rate, and the retirement calculator includes inflation in how much you need to retire.