Historical Inflation Calculator
What was money worth in the past? Enter an amount and a year, and see what it would be worth today, or in any other year. US dollars from 1913, British pounds from 1209, updated to 2026.
$100 in 1970 had the same buying power as approximately
today (September 2026 prices)
Based on US Bureau of Labor Statistics CPI-U data. Years are annual averages; "today" is the latest month, September 2026.
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A pound in 1970 bought roughly what 15 pounds buys today. Most people know inflation exists; very few have a feel for how much it compounds over decades.
This calculator uses official government price index data to convert historical amounts into equivalent modern values. It does not tell you what something cost. It tells you how much purchasing power has changed. A house that cost £5,000 in 1960 is not automatically worth the inflation-adjusted figure today, because supply, demand and local markets all moved on their own. Inflation adjustment is one lens, not the whole picture.
How we work it out
To move an amount from one year to another, we multiply it by the price index for the later year and divide by the price index for the earlier year. If prices doubled between the two years, the amount doubles. The average per year is the steady yearly rate that would produce the same overall change.
Data sources
US figures use the Consumer Price Index for All Urban Consumers (CPI-U) published by the Bureau of Labor Statistics, as annual averages from 1913. UK figures use the consumer price index (CPI): the Office for National Statistics series from 1988, and before that the Bank of England’s long-run consumer price series, which runs back to 1209 and matches the ONS figures from 1988. Before 1988 the UK figures are modelled estimates, chiefly built from the Retail Price Index, so the further back you go the rougher they are. The ONS and BLS figures are annual averages, and “today” uses the latest month published.
Common mistakes
- Comparing wages or prices from different years without adjusting them. $100 in 2000 and $100 now are not the same.
- Assuming your own costs rose the same as prices overall. Rent, food or fuel can move very differently.
- Using figures from the wrong country.
- Expecting an exact answer for a single month. The figures are yearly averages.
Questions
Why does the UK data go back to 1209?
The Bank of England publishes a long-run consumer price series, compiled by economic historians, that runs from 1209 and joins smoothly onto the ONS consumer price index from 1988. The Bank uses the same approach in its own inflation calculator. Before about 1750 prices were patchy, so treat those results as a rough picture.
Why do the UK results use CPI and not RPI?
CPI is the measure the ONS and the Bank of England use for UK inflation. The Retail Price Index runs higher than CPI, so results here will be a little lower than a calculator built on RPI. Before 1988 the CPI figures are modelled from RPI data, so the two agree closely in the earlier years.
How is the average per year worked out?
It is the compound yearly rate that turns the starting price level into the ending one, not the total divided by the number of years. For example, prices doubling over ten years is about 7.2% a year, not 10%.
Is this exact?
No. Inflation indices measure average price changes across a basket of goods that changes over time. Products that did not exist in 1950 cannot be compared to 1950 prices. The result is an estimate of how purchasing power has changed in general, not a precise conversion for any specific item.
Inflation calculated. Research continues.