What an inflation calculator actually tells you
Inflation is the general rise in prices over time, so a dollar buys less later than it does now. An inflation calculator turns that into a concrete comparison: how many dollars in one year have the same buying power as a given number of dollars in another. This page does it two ways. The first uses recorded history, the US Consumer Price Index, to compare two dates between 1913 and September 2026. The second lets you choose an inflation rate and see what a cost would become, or what an old amount would be worth today, if prices rose at exactly that pace. The two are kept apart on purpose, because one is a measurement and the other is a what-if.
The formula behind the historical comparison
The Bureau of Labor Statistics publishes the CPI as an index number. Prices of a fixed basket of goods and services bought by urban households are tracked, and the index is scaled so that the average of 1982 to 1984 equals 100. To compare two dates, divide the later index by the earlier one and multiply by your amount:
equivalent amount = amount × CPI at the end date ÷ CPI at the start date
With the default example, the annual average index was 172.2 in 2000 and 313.689 in 2024. So $1,000.00 in 2000 has the buying power of $1,821.66 in 2024: $1,000.00 × 313.689 ÷ 172.2. Prices were 82.17% higher over 24 years, which is an average of 2.53% a year, compounded.
The calculation also runs backwards. $1,821.66 in 2024 is worth $1,000.00 in 2000, within a cent of the amount we started with. An earlier example: $100.00 in 1980 matches $208.96 in 2000, a rise in prices of 108.96%.
Annual average or exact month?
The calculator offers two bases. An annual average is the mean of the twelve monthly index values for a calendar year, rounded to three decimals, and it smooths out the ups and downs inside a year. It suits questions like what a 2000 salary would be in today's dollars. An exact month compares one specific month with another, which suits a lease signed in a particular month or a price noted on a particular date. For example, $1,000.00 in January 2020 has the buying power of $1,306.12 in September 2026, the latest month published at the time this page was last updated.
Two cautions come with the data. The current year is not finished, so it has no annual average until December is published; use the monthly basis for recent comparisons. And the index for October 2025 was never published by BLS because of the 2025 lapse in appropriations. Because one month is missing, there is no official annual average for 2025 either. The calculator tells you so and leaves the gap blank. It does not fill in a guess, since a made-up number would look exactly like a real one.
Using an assumed rate for the future or the past
Nobody knows future inflation, so the second and third modes ask you to supply the rate. If something costs $1,000.00 today and prices rise at an assumed 3% a year, after ten years it costs $1,343.92: $1,000.00 × 1.03 raised to the power of 10. Working backwards, an amount that would buy what $1,000.00 buys today needed to be only $744.09 ten years ago at the same assumed pace. The result is sensitive to the rate you pick: over ten years, 2% gives $1,218.99, 3% gives $1,343.92 and 4% gives $1,480.24 for the same $1,000.00. Treat these as scenarios, not forecasts. Real inflation changes from year to year, and a negative rate is allowed if you want to test falling prices.
Worked examples
| Question | Answer |
|---|---|
| $1,000 in 2000, in 2024 dollars (annual averages) | $1,821.66 |
| $100 in 1980, in 2000 dollars (annual averages) | $208.96 |
| $1,000 in January 2020, in September 2026 dollars | $1,306.12 |
| $1,000 today at an assumed 3% for 10 years | $1,343.92 |
| Amount 10 years ago equal to $1,000 today, assumed 3% | $744.09 |
What the CPI does not capture
The CPI-U used here measures the average price change for urban consumers across the United States. Your own inflation depends on what you buy. A household that spends a large share on rent, tuition or medical care can see a different rate from the average, and prices differ by region and over time. The index also adjusts for some quality changes, so a comparison across decades is an approximation of buying power, not a promise that the same goods cost exactly that much. For anything with money riding on it, such as a contract or a legal claim, check which index and which dates the other party must use. This page is for general information and is not financial advice.
Where inflation fits into other calculations
A return that looks healthy can disappear once prices are taken into account, which the real return calculator works out directly. The inflation breakeven calculator looks at what market prices imply about future inflation, and the compound interest calculator shows how growth builds on itself, the same arithmetic as the assumed-rate mode here. To express a change as a percentage, use the percentage calculator, and to see whether a raise outpaced prices, compare it with the pay raise calculator result. If you are deciding when to claim Social Security, the Social Security claiming age calculator compares two claiming ages.
Inflation calculator questions
How do I calculate the value of money over time?
Multiply the amount by the CPI at the end date and divide by the CPI at the start date. For $1,000.00 from 2000 to 2024 that is $1,821.66.
Which inflation data does this calculator use?
The CPI for All Urban Consumers (CPI-U), all items, US city average, not seasonally adjusted, published by the US Bureau of Labor Statistics (series CUUR0000SA0). The data on this page was retrieved on 2026-11-06 and runs to September 2026.
Why is there no 2025 annual average?
BLS did not publish the October 2025 index, so there is no complete set of twelve months to average. Use the exact-month basis for dates around then. The calculator does not estimate the missing month.
Can I use this to predict future prices?
No. The future modes apply the constant rate you type in. They show what would happen at that rate, not what will happen. Try several rates to see the range.
Is the result my personal inflation rate?
No. It reflects the average basket for urban consumers. Your own costs may have risen faster or slower depending on what you buy and where you live.
What is the difference between the average per year and the total change?
The total change compares the two end points. The average per year is the constant yearly rate that would produce the same total when compounded, so 82.17% over 24 years is 2.53% a year.