--- title: "Inflation Calculator (CPI, 1913–2025) | Interest Grove" description: "What is an amount from one year worth in another? An inflation calculator built on the BLS CPI-U annual averages from 1913 to 2025." url: https://interestgrove.bond/ --- # Inflation calculator What is an amount from one year worth in another? Pick two years between 1913 and 2025 to compare prices with the U.S. Consumer Price Index, one growth ring for every year in between. ## How the inflation calculator works It scales the amount by the ratio of two Consumer Price Index values. The index is the CPI-U, U.S. city average, all items (BLS series CUUR0000SA0), the measure most often quoted as "inflation". Each year uses its annual average, so the result compares typical prices across whole years. Value in year B = amount × CPI(B) ÷ CPI(A)Average yearly inflation = (CPI(B) ÷ CPI(A))^(1 ÷ years) − 1 The tree rings draw the same history: one ring per year from the inner year outwards, wider when prices rose faster, red at 5% or more, and dashed when the average price level fell, as in 2009 and the early 1930s. Example: $100 in 2000 (CPI 172.2) is $100 × 321.943 ÷ 172.2 = $186.96 in 2025, a rise in prices of about 87%, or 2.5% a year. ### About the data Annual averages from 1913 to 2025, fetched from the BLS Public Data API on 30 October 2026. BLS published no October 2025 index because of the 2025 lapse in appropriations, so its 2025 average covers the other eleven months. The latest monthly index at that point was September 2026 (336.940). ## Sources - U.S. Bureau of Labor Statistics, [CPI for All Urban Consumers (CPI-U), U.S. city average, all items, not seasonally adjusted, series CUUR0000SA0](https://data.bls.gov/timeseries/CUUR0000SA0) (1982–84 = 100): the annual averages, 1913–2025, used here. - U.S. Bureau of Labor Statistics, [Consumer Price Index](https://www.bls.gov/cpi/) home page, and its [CPI Inflation Calculator](https://www.bls.gov/data/inflation_calculator.htm), which uses the same CPI-U series. - Federal Reserve Bank of St. Louis, FRED, [CPIAUCNS](https://fred.stlouisfed.org/series/CPIAUCNS): the same series, used to cross-check the monthly values. ## More in the grove Four more calculators for money and time. - [Purchasing power calculator What your money will lose at an inflation rate you choose, or has lost since a past year.](https://interestgrove.bond/purchasing-power-calculator/) - [Rule of 72 calculator The quick doubling-time rule against the exact answer, with the rules of 70 and 69.3.](https://interestgrove.bond/rule-of-72-calculator/) - [Future & present value calculator Lump sums and regular payments, at the start or end of each period, year by year.](https://interestgrove.bond/future-value-calculator/) - [Real vs nominal return The Fisher equation, exact and approximate, with inflation typed in or taken from CPI history.](https://interestgrove.bond/real-return-calculator/) ## Recommended Two free services for the online side of money research. Disposable email · no sign-up ### CleanTempMail Budget templates, inflation reports and savings newsletters often ask for an email address before you can download them. CleanTempMail gives you a free temporary inbox straight away, with no sign-up, a random or custom address on hundreds of domains, and messages deleted automatically after 3 days. Get the file without adding to your everyday inbox. [Get a free temporary inbox](https://cleantempmail.com/) Disposable cloud browser · free domain lookups ### WebTraceCheck Sent a link to a "high-interest" savings or investment site you have never heard of? WebTraceCheck's free DNS and domain lookup shows the details behind a site's domain, and its disposable cloud browser opens unfamiliar links on an isolated desktop that is deleted after each session. Nothing to install, with free time every day. [Check a website with WebTraceCheck](https://webtracecheck.com/) ## Questions **Why is my answer different from another inflation calculator?** Check which months it compares. This one uses annual averages; a calculator that compares single months, such as a January with a December, can differ by a few percent for the same pair of years. **Is this how prices changed for me?** Not exactly. The CPI-U follows a broad basket bought by urban consumers. Your own mix of rent, fuel, food and fees may have risen faster or slower. **Can I go back in time?** Yes. Put the later year first to see what an amount would have been in an earlier year's dollars. **Why does the data stop at 2025?** 2025 is the latest year with a full annual average. The months of 2026 are not blended into a part-year figure.