$100 in 1990 needed about $246 in 2025 to buy the same things, going by US CPI annual averages. For that kind of look back, use the second calculator; to look ahead, put your expected inflation rate and number of years into the first. Both run in your browser, and neither forecasts prices, exchange rates or returns.
Purchasing-power erosion calculator
Enter an amount, the annual inflation rate you expect, and how many years it sits. It returns the real purchasing power left and how much it lost. Everything is computed in your browser, and the numbers you enter are not sent anywhere.
Enter an amount, an inflation rate and a number of years to see how purchasing power changes.
Convert dollars between years with US CPI
Years from 1970 to 2025. It uses annual averages of the BLS consumer price index for all urban consumers (CPI-U), so it applies to US dollars only.
Enter an amount and two years between 1970 and 2025.
What each input represents
The amount is the nominal cash you want to measure; the annual inflation rate assumes prices rise by the same proportion each year; the years are how long the money remains as cash. The nominal balance does not shrink in the output. Its value relative to today's prices does.
The tool uses P ÷ (1 + i)ⁿ, where P is the amount, i the annual inflation rate and n the years. A constant rate makes a scenario calculable; it does not claim every future year will be identical. At the illustrative 6% input, purchasing power roughly halves in 12 years, the compounding effect approximated by the rule of 72.
What the result can answer
The result answers: if prices change at the rate entered, what would the same nominal amount be worth in today's purchasing power after the selected period? It says nothing about where the dollar will trade and includes no interest, tax, conversion spread or product return. It can compare cash scenarios, but cannot decide a currency switch on its own.
A comparison between local currency and dollars also needs inflation on both sides, conversion costs, exchange-rate movement and the way the dollars are held. For the common ways to hold them, continue to where to park dollars and how the four containers differ.
Turn one answer into a range of scenarios
Set the period to the time you really expect not to touch the money, not a longer one that makes the result look more dramatic. Take the official CPI where you live as a guide and run both the low and the high end of a reasonable range; two results side by side show the uncertainty better than one chosen number.
If you may convert currency or buy a product, list the spread, fees, tax and access limits separately before comparing outcomes.
Where the CPI figures come from
The second calculator uses annual averages of the consumer price index for all urban consumers (CPI-U) published by the Bureau of Labor Statistics, taken from the Minneapolis Fed's historical table that runs back to 1913. The conversion needs only the ratio of the two years' index values: amount × CPI of the target year ÷ CPI of the starting year.
| Year | CPI annual average | $100 that year, in 2025 dollars |
|---|---|---|
| 1970 | 38.8 | about $830 |
| 1980 | 82.4 | about $391 |
| 1990 | 130.7 | about $246 |
| 2000 | 172.2 | about $187 |
| 2010 | 218.1 | about $148 |
| 2019 | 255.7 | about $126 |
| 2022 | 292.7 | about $110 |
| 2025 | 321.9 | $100 |
Read it the other way and $100 from 2019 bought only about $79 worth of goods by 2025; in 2022 alone, prices rose 8% on the year before.
The BLS's own inflation calculator works month by month, so the same two years can give a slightly different answer depending on the months chosen; annual averages give the level for the whole year. The 2026 annual average arrives in early 2027. The latest release covered August 2026, when prices were 3.4% higher than a year earlier.
These are US prices and convert US dollars only. For your own currency, use your national statistics office's CPI and put that rate into the first calculator.