How to use the inflation calculator
- Choose the US or the UK.
- Enter an amount and the year it's from, then the year you want it in: a past year or the latest month.
- Read the value with inflation, the total price change and the average yearly rate. Open Year by year to see each year's CPI and inflation.
Formula
Value in year B = amount × CPI(B) ÷ CPI(A)
Average inflation = (CPI(B) ÷ CPI(A))1 ÷ years − 1
Annual averages stand for the middle of each year, and the latest month for the middle of that month, so the years are counted between those points.
Worked example: $100 from 2000
- CPI-U: 172.2 in 2000 and 321.943 in 2025.
- $100 × 321.943 ÷ 172.2 = $186.96. Prices rose 86.96%.
- Over 25 years: 1.86961/25 − 1 = 2.53% a year.
- From the 2025 average to August 2026, prices rose another 4.05%, so the same $100 from 2000 is about $194.53 now.
- Going back works too: $100 in 2025 had the buying power of $40.60 in 1990.
- UK: £100 in 2000 is £190.37 in 2025 (CPI 72.7 to 138.4).
Tips
- To check whether an investment beat inflation, compare its yearly return from the ROI calculator with the average inflation here.
- Planning ahead? Raise a savings target for future inflation before using the savings goal calculator or the retirement calculator.
- Pay rises below inflation are a real-terms cut: compare with the salary hike calculator.
Data: US Bureau of Labor Statistics, CPI-U (all urban consumers, US city average, all items), 1982–84 = 100, annual averages 1913–2025 and August 2026; Office for National Statistics, Consumer Prices Index (CPI, all items), 2015 = 100, annual averages 1988–2025 and August 2026. Read on 2 October 2026; we add each new year when it's published.