Free UK Inflation Calculator.
UK Inflation Calculator
See what your money was really worth: 1751 to 2026.
CPI: the official measure used for the Bank of England's inflation target.
Open a payslip from ten years ago next to today's one and the number's gone up — but has your money actually gone further, or less far? That's the question an inflation calculator UK households increasingly reach for, especially after the price shocks of 2022 and 2023. The calculator above answers it in seconds, but the numbers behind it are worth understanding properly, so here's the full picture: how UK inflation is worked out, what CPI and RPI actually mean, and what your pound was worth going all the way back to 1751.
How to use this UK inflation calculator
The tool above is built to answer three slightly different questions, depending on what you actually need to know. Here's how to get the most out of it.
- Pick CPI or RPI. CPI is the UK's official measure and the one the Bank of England targets at 2%. RPI is the older measure, still used for things like index-linked gilts and some rent reviews, and it tends to run a little higher. If you're not sure which one to use, CPI is the safer default — more on the difference below.
- Enter an amount and pick your two years. Type in any sum, choose a "from" year and a "to" year, and hit Calculate. Got the years the wrong way round? Tap the swap button between the two dropdowns instead of re-selecting both.
- Try "Since you were born." Drop in your birth year and the calculator will automatically compare it against the latest available year — a quick way to see how much prices have moved across your own lifetime, without picking dates yourself.
- Switch to "Salary check" for pay specifically. This mode reframes the same maths around wages: enter a starting salary and, optionally, what you're actually earning now, and it'll tell you whether your pay has kept pace with the cost of living or fallen behind it in real terms.
- Tap the trend chart. The line underneath your result isn't just decoration — tap or click anywhere on it and you'll see the exact index value and percentage change for that specific year.
How is UK inflation actually calculated?
The maths itself isn't complicated, even though the underlying data collection is a genuinely large operation. Every month, the Office for National Statistics prices out a "basket" of several hundred goods and services — everything from bread and rail fares to streaming subscriptions and haircuts — collected from thousands of shops, websites and service providers across the country. That basket gets turned into a single index number, and the percentage change in that number from one year to the next is the inflation rate you hear about on the news.
To adjust a sum of money for inflation, you multiply it by the ratio between the two index values:
Adjusted amount = Original amount × (Index in target year ÷ Index in starting year)
So if the index was 100 in 2015 and it's 142.5 now, £100 from 2015 needs to become £142.50 today just to buy the same basket of stuff. That's the whole calculation the tool above is running — it's just doing it instantly, across 275 years of data, instead of you looking up index tables by hand.
CPI vs RPI: what's actually the difference?
Whether you're using this as a straightforward CPI calculator UK-wide or specifically comparing it against RPI, this trips a lot of people up, mostly because both numbers get quoted in the news without much explanation. Here's the short version.
| Measure | What it covers | Used for |
|---|---|---|
| CPI (Consumer Prices Index) | Prices of goods and services households buy day to day | Bank of England's 2% inflation target, most official reporting |
| RPI (Retail Prices Index) | Same basket as CPI, plus housing costs like mortgage interest | Index-linked bonds, some rail fares, some rent reviews |
Because RPI includes housing costs and uses an older statistical formula, it almost always comes out higher than CPI over any meaningful stretch of time — sometimes by a full percentage point or more in a given year. Neither one is "wrong"; they're just measuring slightly different things, which is exactly why this calculator lets you toggle between the two rather than picking one for you.
Is RPI higher than CPI right now?
Yes, generally — RPI has run above CPI for most of the last few decades, largely because of how it treats housing costs and the formula effect built into its calculation. It's not guaranteed every single year, but as a long-run pattern, RPI overstating CPI is the norm rather than the exception. Whichever way you're comparing them, using a CPI vs RPI calculator UK-based like this one, built on the same ONS series both figures come from, keeps the comparison consistent rather than mixing sources.
What was £100 worth throughout UK history?
This is where the "how far back does UK inflation data go" question usually comes up. Most inflation calculators online only go back to 1988, sometimes 1950. This one runs all the way to 1751, chain-linking the ONS composite price index and RPI series together with the modern CPI figures so the numbers line up properly at the join. Here's what £100 from a handful of milestone years would need to be today to have the same buying power.
| Year | £100 then is worth this much in 2026 |
|---|---|
| 1751 | £22,770 |
| 1800 | £11,645 |
| 1850 | £12,923 |
| 1900 | £13,235 |
| 1950 | £3,613 |
| 1988 | £287 |
| 2000 | £196 |
| 2015 | £143 |
Notice 1850 and 1900 sit above 1800, not below it. That's not a typo — prices genuinely fell for stretches of the Victorian era, largely thanks to the gold standard, cheaper imported grain, and industrial productivity gains outpacing demand. Inflation isn't a one-way ratchet; it just feels that way because the last eighty years have been so relentlessly upward.
That 1950-to-1988 bar isn't a data error either — it's the 1970s oil shocks and double-digit inflation years doing exactly what they did to household budgets at the time, compounded over nearly four decades. Since 2015, prices are up roughly 42-43%, most of that concentrated in the 2021-2023 stretch when energy costs spiked and the wider cost of living crisis took hold.
Is your salary keeping up with inflation?
This is arguably the more useful question for most people day to day, and it's exactly what the "Salary check" mode above is built for — think of it as a salary vs inflation calculator UK employees can use before a pay review, or simply as a pay rise inflation calculator to sanity-check an offer against the cost of living. A pay rise that sounds generous on paper can still leave you worse off if inflation moved faster underneath it.
The logic is simple: take your salary from an earlier year, run it through the same index-ratio calculation as any other amount, and you get the figure your pay would need to hit today just to stand still in real terms. Anything below that number is effectively a pay cut, even if the number on your payslip has gone up.
How much should my salary have increased with inflation?
As a working rule, your salary needs to have grown by at least the cumulative inflation rate over the period you're checking to have kept the same real-terms buying power. So if CPI has risen 20% since your last salary review, a salary that's only gone up 12% in that time means you're about 8 percentage points behind — worth a genuinely useful number to walk into a pay review with, rather than a vague feeling that things feel tighter than they used to.
Am I getting a pay cut? Using an inflation calculator to check
In real terms, yes, if your rise sits below the inflation rate. Your take-home pay might be a bigger number, but if it buys less than it did before, that's a pay cut in every sense that matters for your weekly shop, rent, or bills — it's just one that doesn't show up as a cut on the payslip itself. This is precisely the gap the salary check mode is designed to expose, rather than leaving you to do the sums in your head.
Frequently asked questions
What is the difference between CPI and RPI?
CPI (Consumer Prices Index) is the UK's official inflation measure and the one behind the Bank of England's 2% target. RPI (Retail Prices Index) covers a similar basket of goods but also includes housing costs like mortgage interest, and it's calculated with an older statistical method that tends to push the number higher. They usually move together but rarely match exactly.
How much has inflation increased since 2015 in the UK?
Based on ONS CPI data, prices have risen by roughly 42-43% cumulatively between 2015 and 2026, working out to an average of just under 3.3% a year over that stretch — though the year-to-year rate varied enormously, from near-zero in the mid-2010s to double digits during the 2022 energy crisis.
How far back does UK inflation data go?
Official ONS Consumer Prices Index data starts in 1988. Before that, economic historians have reconstructed a composite price index stretching back to 1750 using retail price records, wage data and earlier government price series, which is what powers this calculator's 1751-2026 range once chain-linked to the modern CPI figures.
What's a purchasing power calculator UK-based like this actually measuring?
It's measuring how much a fixed sum of money can buy at two different points in time, once you strip out the effect of rising prices. £1 today buying less than £1 did a decade ago is a fall in purchasing power — the calculator above turns that abstract idea into an actual pound figure you can compare directly.
Can I use this as a historical inflation calculator for old savings or wages?
Yes — that's one of the more common uses. Whether you're checking what a grandparent's 1960s wage would be worth now, sense-checking an old family story about house prices, or working out the modern equivalent of a Victorian-era sum for a school project, the 1751-2026 range covers it.
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