Find the real inflation rate between two prices or two years
💡 Why This Matters "Prices went up 20% over 5 years" and "prices went up 4% a year" describe the same thing very differently. This tool gives you both the total change and the average yearly rate, using either your own two prices or official CPI data for any two years.
1918 holds the record for the highest annual U.S. inflation rate in the modern CPI era at +18.0%, driven by wartime spending competing with civilians for the same scarce goods.
As an Amazon Associate we earn from qualifying purchases.
We do our best to link products that we genuinely believe are organic, no disposable junk, sustainable, and built to last.
Inflation rate = (final price − initial price) ÷ initial price × 100. This works with any two prices from two points in time, or with official CPI index values for two years. If you provide the number of years, this calculator also computes the average annual rate — the constant yearly rate that would compound to the same total change.
A positive rate means prices rose (inflation, the normal long-run direction); a negative rate means prices fell (deflation, less common but not unheard of). Cumulative inflation tells you the total change over the whole period; average annual inflation lets you compare periods of different lengths on equal footing.
The "Two Prices" mode is only as accurate as the two prices you provide — a single product's price history won't necessarily match the broader economy. The "By Year (CPI)" mode uses the same official BLS data as the Buying Power calculator, covering 1913 through 2024, and reflects the overall economy rather than any one specific item.
Use the cumulative rate to see the total damage inflation has done over a stretch of time, and the average annual rate to compare that stretch against a "typical" year (historically, the U.S. long-run average annual rate has hovered around 2-3%). For converting an actual dollar amount rather than finding a rate, use the Buying Power calculator instead.
Example: A basket of food cost $100 and now costs $300. Cumulative inflation = ($300 − $100) ÷ $100 × 100 = 200%. Using CPI data instead, comparing 1918 (CPI 15.1) to 2018 (CPI 251.1) gives cumulative inflation of about 1,563% over that century — an average annual rate of roughly 2.85% a year, compounded.
Inflation rate = (final price − initial price) ÷ initial price × 100. This works with any two prices or price index values from two points in time.
Cumulative inflation is the total percentage change over the whole period. Average annual inflation is the compound yearly rate that would produce that same total change — useful for comparing periods of different lengths on equal footing.
Buying Power converts a specific dollar amount from one year into its equivalent in another year. This calculator instead reports the inflation rate itself — the percentage change — which is useful when you want the rate rather than a converted dollar figure.