UK Inflation Calculator
See what a sum of money from any year since 1950 is worth in today's pounds, using historic UK CPI inflation data from the ONS. Compare purchasing power across decades in one click.
UK inflation calculator
What money from the past is worth today (CPI-based).
Based on ONS CPI annual averages. A guide for purchasing power, not an official ONS figure.
What is the UK inflation calculator?
Inflation measures how the general level of prices rises over time, which means the same number of pounds buys less as the years pass. This tool uses the UK Consumer Prices Index (CPI) published by the Office for National Statistics to translate a sum of money from one year into its equivalent purchasing power in another.
Because of cumulative inflation, £100 in 1990 has roughly the same buying power as about £250 today. The further back you go, the larger the gap — £100 in 1970 is worth well over £1,000 in modern money.
How inflation is measured in the UK
The ONS tracks a representative "basket" of around 700 goods and services — from bread and bus fares to streaming subscriptions — and records how the total cost changes each month. The percentage change over twelve months is the headline inflation rate you hear in the news. CPI is the measure used for the Bank of England's 2% target and for uprating many benefits and pensions.
Why purchasing power matters
Understanding inflation helps you judge whether a pay rise is real or just keeping pace with prices, whether savings are losing value in a low-interest account, and how historic prices compare to today. A salary that looked generous a decade ago may buy noticeably less now.
Example. If your grandparents bought a house for £20,000 in 1980, that sum is equivalent to roughly £90,000 in today's money once cumulative inflation is applied — a useful reminder that headline house-price growth is partly an inflation story.
CPI vs RPI
You may also see the older Retail Prices Index (RPI), which typically runs about one percentage point higher than CPI because of differences in how it is calculated. CPI is now the ONS's lead measure; RPI is being phased out. This calculator uses CPI annual averages for consistency.
For the official series and the latest monthly rate, see the ONS inflation and price indices pages.
Frequently asked questions
How does the UK inflation calculator work?
It uses ONS Consumer Prices Index annual averages. We divide the price index of your target year by the index of your starting year and multiply your amount — giving the equivalent purchasing power.
What is £100 in 1990 worth today?
Roughly £250 in today's money, based on cumulative CPI inflation. Enter your own years above for an exact figure.
What is the difference between CPI and RPI?
Both measure inflation, but RPI usually shows a higher rate because of how it is averaged and what it includes (such as mortgage interest). CPI is the ONS's headline measure and is used for the Bank of England's 2% target.
Why does money lose value over time?
When prices rise across the economy, each pound buys fewer goods and services. That erosion of purchasing power is what we call inflation.
Is this an official ONS figure?
No. It is a close estimate using ONS CPI annual averages and is intended as a guide. For exact, dated figures use the ONS inflation pages directly.