Inflation calculator
See what money was worth in past years, or what inflation may do to a price.
- Formula and assumptions shown
- Table and CSV export
- Runs in your browser
How it works
Historical mode restates an amount from one year in another year's dollars with the US Consumer Price Index for All Urban Consumers (CPI-U). It multiplies the amount by the ending year's index divided by the starting year's index, then shows cumulative inflation, the average yearly rate, the change in purchasing power, and the value in every year between the two.
Historical: value = amount × (ending-year CPI ÷ starting-year CPI); average yearly inflation = (later CPI ÷ earlier CPI)^(1 ÷ years) − 1. Future: future equivalent cost = cost today × (1 + inflation)^years; today's-dollar value of the same fixed amount = amount ÷ (1 + inflation)^years.
Full years use the Bureau of Labor Statistics annual average. The current year uses the latest published month and is labelled that way, because one month is not a full-year average. The ending year can be earlier than the starting year to convert an amount back into older dollars.
Future projection mode multiplies today's entered cost by an inflation factor to estimate its future equivalent cost, and divides the same dollar amount by that factor to show what a fixed nominal amount in the future would equal in today's dollars. Its rate is your assumption, not a CPI measurement or a forecast.
Assumptions
- Historical figures use the CPI-U, U.S. city average, all items, not seasonally adjusted (1982–84 = 100), bundled with the page and updated by hand; nothing is fetched.
- The latest year uses a single month's index, not an annual average, and counts as one year after the previous full year in the average yearly rate.
- The CPI measures average price changes for urban consumers; your own costs can rise faster or slower.
- In future projection mode, inflation is compounded once per modeled year at the constant rate you enter.
- Investment returns, taxes, fees, withdrawals, and changing spending are excluded.
Worked example
Worked examples on this page use US dollars.
$100 from 2000 in 2025 dollars
The CPI-U annual average was 172.2 in 2000 and 321.943 in 2025, so $100 × (321.943 ÷ 172.2) = about $186.96. Prices rose about 86.96% over those 25 years, an average of about 2.53% a year.
Step by step
- Look up the index for each year. The CPI-U annual average was 172.2 in 2000 and 321.943 in 2025.
- Divide the later index by the earlier one. 321.943 ÷ 172.2 = 1.869588, so prices were about 86.96% higher in 2025 than in 2000.
- Restate the amount. $100 × 1.869588 = $186.96. That is the Equivalent value: $100 in 2000 bought about what $186.96 bought in 2025.
- Find the average yearly rate. Over the 25 years, 1.869588^(1 ÷ 25) − 1 = 2.53% a year, the same calculation as CAGR.
- Check purchasing power. A dollar in 2025 buys 1 ÷ 1.869588 = 0.534877 of what it bought in 2000, a purchasing power change of −46.51%.
How to read your result
Equivalent value is the amount restated in the ending year’s dollars. Cumulative inflation is the total rise in the index between the two years, and the average yearly rate spreads that rise evenly over the years between them. Purchasing power change runs the other way: it is how much less a dollar buys in the later year. The table lists the index and the restated value for every year in the range, with each year’s change from the year before.
Choosing an ending year before the starting year converts an amount back into older dollars: $100 in 2025 is worth $53.49 in 2000 dollars. The rates are still measured forward in time, so cumulative inflation stays 86.96%. The newest year, 2026, uses the August 2026 index, a single month rather than a full-year average, so it is labelled as the latest month and will move as later months are published.
Future projection mode answers a different question with a rate you choose. At 2% for ten years the factor is 1.02^10 = 1.218994, so prices are about 21.9% higher: a $10,000 cost today becomes a future equivalent cost of $12,189.94, an Increase of $2,189.94, and a fixed $10,000 received in year ten is worth $10,000 ÷ 1.218994 = $8,203.48 in today’s dollars. After one year the table shows $10,200 and $9,803.92. The rate stays constant for the whole term, and no investment return is added; to see growth and inflation together, compare a compound interest projection with this mode’s today’s-dollars figure over the same years.
What changes the result most
- Starting year
- The further back the starting year, the more the index has risen. $100 from 1980 is $390.71 in 2025 dollars, an average of 3.07% a year; $100 from 2020 is $124.39, an average of 4.46% a year over five years.
- Inflation rate (future projection)
- At 3% instead of 2% over ten years, the future cost of $10,000 is $13,439.16 and a fixed $10,000 is worth $7,440.94 in today’s dollars.
- Time (future projection)
- At 2% over 20 years, the future cost is $14,859.47 and the today’s-dollar value falls to $6,729.71. At 3% over 20 years the figures are $18,061.11 and $5,536.76.
Questions
Does it use live inflation data?
No. Historical mode uses Bureau of Labor Statistics CPI-U figures that are built into the page, from 1913 through the August 2026 index, and are updated by hand rather than fetched. Future projection mode uses the rate you enter.
Why is 2026 marked as the latest month?
The annual average for a year is published only after December. Until then the calculator uses the most recent monthly index, August 2026, so figures for 2026 compare one month with full-year averages and will change as new months are released.
What does future equivalent cost mean?
It estimates how much money may be needed in the future to buy what today's cost represents under the entered inflation assumption.
Can I include investment returns?
No. This page isolates purchasing-power change. Use the compound interest calculator when you also want contributions and an assumed return.
How do you calculate the inflation rate?
Divide the later price index value by the earlier one, subtract 1, and multiply by 100. With the Consumer Price Index, (CPI in the later month ÷ CPI in the earlier month − 1) × 100 gives the percentage change. For an average yearly rate over several years, raise the ratio to the power of 1 ÷ years before subtracting 1, the same calculation as CAGR.
How is the inflation rate measured?
In the United States the most cited measure is the Consumer Price Index from the Bureau of Labor Statistics, which tracks the average change over time in prices paid by urban consumers for a market basket of goods and services. Historical mode uses its CPI-U annual averages; future projection mode applies the constant rate you enter instead.
More in Savings & investing
Sources
- BLS: Consumer Price Index (CPI-U data and releases)
- BLS: purchasing power and constant dollars
- Investor.gov compound interest calculator
These references explain the concepts behind the calculation. They do not endorse this site. Estimates leave out any cost or condition you did not enter.