How to Calculate the Inflation Rate from CPI?
(CPI ₂ − CPI₁) ÷ CPI₁ × 100 — where CPI₁ is the Consumer Price Index at your start date and CPI₂ is the index at your end date. For example, from January 2020 (CPI 257.971) to July 2026 (CPI 333.918), the inflation rate was 29.44%. Use the free calculator below with official BLS CPI-U data from 1913 to do it instantly, or convert a dollar amount to see how much purchasing power it lost.Use the free CPI inflation calculator below — pick a start and end month, then press Calculate.
CPI data: BLS CPI-U (all items, U.S. city average, 1982–84 = 100), monthly from January 1913. October 2025 was never published by BLS and is estimated when used. Free to use — no sign-up needed.
| Year | Avg CPI | Inflation vs prior year |
|---|
How to Calculate the Inflation Rate from CPI, Step by Step
Calculating the inflation rate from CPI data only takes two index values and one division. Here is the step-by-step method:
- Find the CPI for your start date — for example, the CPI-U in January 2020 was 257.971.
- Find the CPI for your end date — the CPI-U in July 2026 was 333.918.
- Subtract the old CPI from the new CPI: 333.918 − 257.971 = 75.947.
- Divide by the old CPI: 75.947 ÷ 257.971 = 0.2944.
- Multiply by 100 to get a percentage: 0.2944 × 100 = 29.44%.
That is the total inflation over the period. Over those 78 months the average annual inflation rate was about 4.0% per year — the calculator above shows both numbers, plus a month-by-month chart and the yearly breakdown.
The CPI Inflation Rate Formula
The formula to calculate the inflation rate from CPI is:
Inflation Rate = [(CPI₂ − CPI₁) / CPI₁] × 100
CPI₁ is the Consumer Price Index at the beginning of the period and CPI₂ is the index at the end. Because you are always comparing two published index values, the exact same formula is used for a month, a quarter, a year, or 50 years:
How to calculate the cpi inflation rate month over month (MoM)
Plug in two consecutive months. The CPI went from 326.785 in February 2026 to 330.213 in March 2026, so the monthly inflation rate was (330.213 − 326.785) ÷ 326.785 × 100 = +1.05%. Monthly numbers bounce around and are usually reported at an annualized rate; the year-over-year number is the one headline inflation refers to.
How to calculate the rate of inflation using CPI year over year (YoY)
Compare the same month one year apart. With the latest data, July 2026 (333.918) vs July 2025 (323.048) gives a year-over-year inflation rate of 3.36%. That is the standard “current inflation rate” reported in the news.
How to calculate inflation rate using CPI for a full calendar year
Use the December-to-December comparison: December 2025 (324.054) vs December 2024 (315.605) gives 2025 inflation of 2.68%. Economists also cite the annual-average method: the 2025 average CPI (321.943) vs the 2024 average (313.689) is 2.6%. The table below lists both for every year back to 1913.
How to Calculate CPI with the Inflation Rate (Reverse Calculation)
Need to go the other way — from a known inflation rate to the expected CPI? Just rearrange the formula:
CPI₂ = CPI₁ × (1 + Inflation Rate ÷ 100)
Example: the 2021 average CPI was 270.970 and the 2022 average inflation rate was 8.0%. So CPI₂ = 270.970 × 1.080 = 292.65 — almost exactly the published 2022 average of 292.655. This reverse method is how you estimate next year’s CPI from a predicted rate, for example when adjusting contract prices or benefits.
How to Calculate CPI Inflation for a Dollar Amount (Purchasing Power)
To see what a dollar amount from the past is worth today (or the reverse), multiply by the CPI ratio:
Equivalent Value = Amount × (CPI₂ / CPI₁)
Example: $100 in January 2020 × (333.918 / 257.971) = $129.44 in July 2026 — that is, you would need $129.44 in July 2026 to buy the same basket of goods that cost $100 in January 2020. In purchasing-power terms, $100 in early 2020 is now worth only $100 ÷ 1.2944 = $77.25. Use the Dollar Value tab of the calculator above and it computes all of this automatically, with a chart of the dollar’s erosion over time.
What Is the Current U.S. Inflation Rate?
Based on the latest official BLS data through July 2026 (CPI-U 333.918):
| Measure | Period | Rate |
|---|---|---|
| Year-over-year (Jul 2026 vs Jul 2025) | Latest 12 months | 3.36% |
| Full-year 2025 (Dec vs Dec) | 2025 | 2.68% |
| Full-year 2025 (annual average) | 2025 | 2.6% |
| Full-year 2024 (annual average) | 2024 | 2.9% |
| Full-year 2022 (annual average) | 2022 | 8.0% |
All historical values in this table come from the BLS series used by the calculator, so the numbers match what you get when you run the tool.
Annual CPI Averages and Inflation Rates, 1913–2025
The table below shows the calendar-year average CPI-U and the annual inflation rate (average vs prior year average) for every year since 1913. The 2026 average is omitted because 2026 data is only published through July.
| Year | Avg CPI | Inflation % | Year | Avg CPI | Inflation % |
|---|---|---|---|---|---|
| 1913 | 9.9 | n/a | 1914 | 10.0 | 1.0 |
| 1915 | 10.1 | 1.0 | 1916 | 10.9 | 7.9 |
| 1917 | 12.8 | 17.4 | 1918 | 15.1 | 18.0 |
| 1919 | 17.3 | 14.6 | 1920 | 20.0 | 15.6 |
| 1921 | 17.9 | -10.5 | 1922 | 16.8 | -6.1 |
| 1923 | 17.1 | 1.8 | 1924 | 17.1 | 0.0 |
| 1925 | 17.5 | 2.3 | 1926 | 17.7 | 1.1 |
| 1927 | 17.4 | -1.7 | 1928 | 17.1 | -1.7 |
| 1929 | 17.1 | 0.0 | 1930 | 16.7 | -2.3 |
| 1931 | 15.2 | -9.0 | 1932 | 13.7 | -9.9 |
| 1933 | 13.0 | -5.1 | 1934 | 13.4 | 3.1 |
| 1935 | 13.7 | 2.2 | 1936 | 13.9 | 1.5 |
| 1937 | 14.4 | 3.6 | 1938 | 14.1 | -2.1 |
| 1939 | 13.9 | -1.4 | 1940 | 14.0 | 0.7 |
| 1941 | 14.7 | 5.0 | 1942 | 16.3 | 10.9 |
| 1943 | 17.3 | 6.1 | 1944 | 17.6 | 1.7 |
| 1945 | 18.0 | 2.3 | 1946 | 19.5 | 8.3 |
| 1947 | 22.3 | 14.4 | 1948 | 24.1 | 8.1 |
| 1949 | 23.8 | -1.2 | 1950 | 24.1 | 1.3 |
| 1951 | 26.0 | 7.9 | 1952 | 26.5 | 1.9 |
| 1953 | 26.7 | 0.8 | 1954 | 26.9 | 0.7 |
| 1955 | 26.8 | -0.4 | 1956 | 27.2 | 1.5 |
| 1957 | 28.1 | 3.3 | 1958 | 28.9 | 2.8 |
| 1959 | 29.1 | 0.7 | 1960 | 29.6 | 1.7 |
| 1961 | 29.9 | 1.0 | 1962 | 30.2 | 1.0 |
| 1963 | 30.6 | 1.3 | 1964 | 31.0 | 1.3 |
| 1965 | 31.5 | 1.6 | 1966 | 32.4 | 2.9 |
| 1967 | 33.4 | 3.1 | 1968 | 34.8 | 4.2 |
| 1969 | 36.7 | 5.5 | 1970 | 38.8 | 5.7 |
| 1971 | 40.5 | 4.4 | 1972 | 41.8 | 3.2 |
| 1973 | 44.4 | 6.2 | 1974 | 49.3 | 11.0 |
| 1975 | 53.8 | 9.1 | 1976 | 56.9 | 5.8 |
| 1977 | 60.6 | 6.5 | 1978 | 65.2 | 7.6 |
| 1979 | 72.6 | 11.3 | 1980 | 82.4 | 13.5 |
| 1981 | 90.9 | 10.3 | 1982 | 96.5 | 6.2 |
| 1983 | 99.6 | 3.2 | 1984 | 103.9 | 4.3 |
| 1985 | 107.6 | 3.6 | 1986 | 109.6 | 1.9 |
| 1987 | 113.6 | 3.6 | 1988 | 118.3 | 4.1 |
| 1989 | 124.0 | 4.8 | 1990 | 130.7 | 5.4 |
| 1991 | 136.2 | 4.2 | 1992 | 140.3 | 3.0 |
| 1993 | 144.5 | 3.0 | 1994 | 148.2 | 2.6 |
| 1995 | 152.4 | 2.8 | 1996 | 156.9 | 3.0 |
| 1997 | 160.5 | 2.3 | 1998 | 163.0 | 1.6 |
| 1999 | 166.6 | 2.2 | 2000 | 172.2 | 3.4 |
| 2001 | 177.1 | 2.8 | 2002 | 179.9 | 1.6 |
| 2003 | 184.0 | 2.3 | 2004 | 188.9 | 2.7 |
| 2005 | 195.3 | 3.4 | 2006 | 201.6 | 3.2 |
| 2007 | 207.3 | 2.8 | 2008 | 215.303 | 3.8 |
| 2009 | 214.537 | -0.4 | 2010 | 218.056 | 1.6 |
| 2011 | 224.939 | 3.2 | 2012 | 229.594 | 2.1 |
| 2013 | 232.957 | 1.5 | 2014 | 236.736 | 1.6 |
| 2015 | 237.017 | 0.1 | 2016 | 240.007 | 1.3 |
| 2017 | 245.120 | 2.1 | 2018 | 251.107 | 2.4 |
| 2019 | 255.657 | 1.8 | 2020 | 258.811 | 1.2 |
| 2021 | 270.970 | 4.7 | 2022 | 292.655 | 8.0 |
| 2023 | 304.702 | 4.1 | 2024 | 313.689 | 2.9 |
| 2025 | 321.943 | 2.6 | — | — | — |
Sources: U.S. Bureau of Labor Statistics (CPI-U, all items, U.S. city average). Inflation % is the calendar-year average versus the previous calendar-year average.
CPI Inflation Calculator vs. the BLS Inflation Calculator
The official BLS Inflation Calculator, the Minneapolis Fed calculator, and calculator.net are the reference tools in this space. Here is how this calculator compares:
| Feature | This calculator | BLS (bls.gov) | Minneapolis Fed | calculator.net |
|---|---|---|---|---|
| Inflation rate between two dates | Yes, any two months | Yes | Yes | Yes |
| Dollar value / purchasing power | Yes | Yes | Yes | Yes |
| Data range | Jan 1913 – Jul 2026 | 1913 – present | 1913 – present | 1913 – present |
| Average annual rate | Yes | — | — | — |
| Chart of the period | Yes | — | — | — |
| Year-by-year breakdown table | Yes | — | — | Yearly values |
| Step-by-step formula guide | Yes | — | — | — |
| Account / payment required | No | No | No | No |
All of these tools base their numbers on the same official BLS CPI-U series, so results agree with each other (to the last digit, once rounding to cents is accounted for). The BLS tool remains the authoritative reference; this page simply makes the same math faster to run and explains the formula step by step.
What Goes Into the CPI (and Why It Matters)
The CPI-U tracks the out-of-pocket prices of a fixed market basket of goods and services purchased by U.S. urban households. The biggest categories are housing (about 36% of the index), transportation, food and beverages, and medical care. When the CPI rises, each dollar buys less — which is inflation. Knowing how to calculate the inflation rate from CPI lets you:
- Check whether a salary raise actually keeps up with the cost of living.
- Adjust rent, contract, or alimony payments that are indexed to inflation.
- Compare prices from different years when researching historical purchases.
- Understand headlines like “CPI up 3.4% year over year” and verify them yourself.
The calculator on this page deliberately uses the not-seasonally-adjusted CPI-U series (CUUR0000SA0) for two reasons: it is the same series the BLS inflation calculator uses, and it is the correct series for comparing an exact calendar month across years.
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FAQ
Use the formula (CPI₂ − CPI₁) ÷ CPI₁ × 100, where CPI₁ is the index at the start date and CPI₂ is the index at the end date. From January 2020 (257.971) to July 2026 (333.918) that gives (333.918 − 257.971) ÷ 257.971 × 100 = 29.44%.
The CPI inflation rate formula is: [(CPI₂ − CPI₁) / CPI₁] × 100. Keep the two dates consistent — both index values come from the same published BLS CPI series, so the formula works for any period length.
Compare the same month in consecutive years. For example, July 2026 (333.918) vs July 2025 (323.048): (333.918 − 323.048) ÷ 323.048 × 100 = 3.36%. That is the year-over-year rate most news reports cite.
Rearrange the formula to CPI₂ = CPI₁ × (1 + rate ÷ 100). With a predicted 3% rate on a base CPI of 300, the expected new CPI is 300 × 1.03 = 309. This is how future index levels are estimated from forecast rates.
Calculators that use the official BLS CPI-U series produce the same results as the government’s own inflation calculator. Differences of a few cents or hundredths of a percent can appear only from rounding, not from methodology. This calculator also flags the one genuinely missing data point (October 2025, unpublished due to the 2025 appropriations lapse) and estimates it by averaging the surrounding months.
As of the latest BLS report (through July 2026), the year-over-year inflation rate was 3.36%. Full-year 2025 inflation was 2.68% (December to December) or 2.6% (annual average).
The BLS inflation calculator — the official reference — uses the not-seasonally-adjusted CPI-U series, which is the correct measure when you compare the same calendar month across different years. Seasonally adjusted values are useful for month-over-month trend analysis, not for dollar conversions.
Free Online Calculators
Quick Inflation Formulas
- Rate: (CPI₂ − CPI₁) ÷ CPI₁ × 100
- Avg per year: ((CPI₂ ÷ CPI₁)^(12/months) − 1) × 100
- Reverse: CPI₂ = CPI₁ × (1 + rate/100)
- Dollar value: Amount × (CPI₂ ÷ CPI₁)
- Purchasing power: 1 ÷ (1 + total rate)
About This Data
- Series: BLS CPI-U CUUR0000SA0
- Scope: All items, U.S. city average
- Base: 1982–84 = 100
- Range: Jan 1913 – Jul 2026
- Updated: August 2026 (July 2026 data)