Inflation Calculator

An inflation calculator converts dollars between years with the Consumer Price Index: value in year B = value in year A × CPI(B) ÷ CPI(A). Using official BLS annual averages, $100 in 1990 (CPI 130.7) equals $100 × 321.943 ÷ 130.7 ≈ $246.32 in 2025 (CPI 321.943), a cumulative inflation of 146.32%.

How to use the inflation calculator

1. Pick a tab: Dollar value to convert an amount between years, Total inflation for the cumulative percent change, Average rate for the yearly inflation rate between two years, or Future to see what money will buy at an inflation rate you choose.
2. Enter the amount and choose the two years. Any year from 1913 to 2025 works, and the To list also offers the latest month, September 2026. Choose a later year first to convert today’s dollars back into an earlier year.
3. Read the answer, then open Show steps to see the CPI ratio worked with your numbers. The chart highlights your years on the CPI line, and the year-by-year table lists each year’s index and inflation rate.

CPI inflation formula

The Consumer Price Index is a price level: it compares what a fixed basket of goods and services costs at different times. The BLS describes the CPI as representing “changes in prices of all goods and services purchased for consumption by urban households.” The index is set so that the 1982–84 average equals 100.

Value in year B = Value in year A × CPI(B) ÷ CPI(A)

Cumulative inflation = (CPI(B) − CPI(A)) ÷ CPI(A) × 100

Average yearly inflation = (CPI(B) ÷ CPI(A))^{1 ÷ n} − 1, where n is the number of years between them.

The fraction CPI(B) ÷ CPI(A) is the CPI ratio. It says how many times as much the same basket cost in year B. Multiplying an amount by the ratio moves it forward in time; dividing moves it back.

Worked example: $100 from 1990 in 2025 dollars

1. Look up the annual average CPI-U: 130.7 for 1990 and 321.943 for 2025.
2. CPI ratio: 321.943 ÷ 130.7 ≈ 2.463221. Prices in 2025 were about 2.46 times their 1990 level.
3. Value: $100 × 2.463221 ≈ $246.32.
4. Cumulative inflation: (321.943 − 130.7) ÷ 130.7 ≈ 1.463221, or 146.32%.
5. Average yearly rate over n = 35 years: 2.463221^{1 ÷ 35} − 1 ≈ 0.0261, about 2.61% a year.

Run it backwards and $100 in 2025 had the buying power of about $40.60 in 1990.

Worked example: is a raise keeping up with inflation?

Someone earned $50,000 in 2000. To have the same buying power in 2025, the salary would need to be $50,000 × 321.943 ÷ 172.2 ≈ $93,479.38. A 2025 salary below that buys less than the 2000 salary did, even though the number is larger.

Worked example: average inflation from 2020 to 2025

The CPI ratio is 321.943 ÷ 258.811 ≈ 1.243931, so prices rose 24.39% in total. Over 5 years the average rate is 1.243931^{1 ÷ 5} − 1 ≈ 0.044622, about 4.46% a year. Dividing 24.39% by 5 gives 4.88%, which is too high because it ignores compounding. This is the same math as a compound annual growth rate.

Future purchasing power at an assumed rate

No one knows future inflation, so the Future tab uses a rate you choose. At 3% a year, prices after 20 years are 1.03²⁰ ≈ 1.806111 times today’s, so goods that cost $100 today would cost about $180.61, and $100 then buys what $55.37 buys today. At 3%, prices double in about ln 2 ÷ ln 1.03 ≈ 23.4 years; the rule of 70 gives a close estimate of 70 ÷ 3 ≈ 23.3 years.

What $100 from past years is worth in 2025

Values use annual average CPI-U from the BLS. The average rate is the compound yearly rate from that year to 2025.

Yearly inflation rates, 2016 to 2025

Each rate is the change in the annual average CPI-U from the year before: 1.3% (2016), 2.1% (2017), 2.4% (2018), 1.8% (2019), 1.2% (2020), 4.7% (2021), 8.0% (2022), 4.1% (2023), 2.9% (2024) and 2.6% (2025). Prices can also fall: from 1929 to 1933 the index dropped from 17.1 to 13.0, a change of −23.98%, so $100 in 1929 equaled about $76.02 in 1933.

About the CPI data on this page

• Series: CPI-U, U.S. city average, all items, not seasonally adjusted (BLS series CUUR0000SA0), 1982–84 = 100. The BLS says the CPI-U covers over 90 percent of the total population.
• Years 1913–2020: annual averages from the BLS historical CPI-U table. 2021–2025: the average of the published monthly values in the BLS historical table, which reproduces the published 2020 average exactly.
• 2025: October 2025 was not collected because of the 2025 lapse in appropriations. As the BLS explains, the 2025 annual average is the average of the 11 published months: 321.943.
• Latest month: September 2026, 336.940. Last year with a full annual average: 2025. Data retrieved November 1, 2026. When BLS publishes the 2026 annual average, it will be added.

Annual averages smooth out the months, so a month-to-month comparison, such as the BLS CPI Inflation Calculator gives, can differ a little. The CPI is an average for urban consumers; your own costs may have changed faster or slower. Results are estimates for learning and planning, not financial advice.

Common inflation mistakes

• Subtracting index points instead of dividing. A rise of 10 points means much more when the index is 50 than when it is 300. Always use the ratio.
• Dividing the total by the years. 24.39% over 5 years is about 4.46% a year compounded, not 4.88%.
• Mixing indexes. Use the same series (here CPI-U) for both years.
• Treating a past average as a forecast. Future inflation can be higher or lower than any past period.

Sources

Checked in November 2026.

• BLS: Historical CPI-U, U.S. city average, all items, index averages (1913–2020)
• BLS: Consumer Price Index historical tables for U.S. city average (monthly, through September 2026)
• BLS: 2025 lapse in appropriations, impact on the CPI (FAQ)
• BLS: Consumer Price Index overview
• BLS: CPI Inflation Calculator
• Federal Reserve Bank of Minneapolis: Consumer Price Index, 1913–

Inflation practice quiz: 10 questions

Test yourself with 10 multiple-choice questions. Choose an answer and press Submit to see if you are right and why. Your score appears at the end.

Frequently asked questions

How do you calculate inflation between two years?

Divide the CPI of the later year by the CPI of the earlier year, subtract 1 and multiply by 100. From 1990 (130.7) to 2025 (321.943): 321.943 ÷ 130.7 − 1 ≈ 1.4632, so prices rose 146.32%.

How much is $100 from 1990 worth today?

In 2025 dollars, $100 from 1990 is worth about $246.32. Measured to the latest month, September 2026, it is about $257.80.

What was the inflation rate in 2025?

Comparing annual averages, the CPI-U rose from 313.689 in 2024 to 321.943 in 2025, which is 2.6%. Figures based on December-to-December or monthly changes can differ slightly.

How do I calculate the average annual inflation rate?

Take the CPI ratio to the power 1 ÷ n and subtract 1. From 2020 to 2025: 1.243931^{1 ÷ 5} − 1 ≈ 4.46% a year. This is a compound rate, like CAGR.

Why does this calculator differ slightly from others?

Calculators that compare single months, or that estimate the current year, will not match one that uses full-year annual averages exactly. This page shows the CPI values it uses, so you can check every result.

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