Historical Inflation & Purchasing Power Calculator
Enter an amount and two years to see what money was worth, with a chart of how purchasing power changed over time. Uses official US CPI-U and UK RPI data. Nothing uploaded.
Inflation-adjusted value
Learn more: what inflation did to your money
How the adjustment works
The calculator multiplies your amount by the price index in the target year divided by the index in the starting year. In the US CPI-U table it holds, $100 in 1980 (index 82.4) becomes about $381 in 2024 (index 313.7), because 313.7 / 82.4 is 3.81. The annualized rate is the constant yearly change that gives the same total, here about 3.1% a year over 44 years.
The annualized rate also lets you compare date ranges. A 100% rise over 40 years is about 1.75% a year, while a 100% rise over 10 years is about 7.2% a year.
The UK figures use RPI
The UK dataset uses the Retail Prices Index. On that index £100 in 1980 (index 60.3) becomes about £627 in 2024 (index 378.0), an annualized 4.3%. The US and UK results come from different indexes and are not a currency conversion. Each shows what a unit of that currency bought in its own country.
The ONS's article on the shortcomings of the RPI says that RPI lost its status as a National Statistic in 2013 and that the ONS does not think it is a good measure of inflation and discourages its use. It says the RPI's formula effect has on average added 0.7 percentage points a year compared with CPIH. Treat the UK figures as an RPI result that likely overstates the loss of purchasing power compared with other measures.
FAQ
Why do the US and UK results differ?
They use different indexes built from different baskets and methods, so the same years give different totals. The UK figure uses RPI, which the ONS says tends to run higher than other measures because of its formula.
What does the annualized rate mean?
It turns the total change over your date range into a single constant yearly percentage. It does not show that inflation was steady, since the real rate varied a lot from year to year.
Can I check whether my salary kept up with inflation?
Yes. Enter your starting salary and year, then compare the adjusted figure with your current pay. If your pay is lower, your real income has fallen even if the number on your payslip has risen.