UK Inflation Calculator

Convert any amount between two years using the official ONS Consumer Prices Index. See the CPI index values behind every result, the cumulative price change and the average annual rate — or project a future rate you choose.

Last revised 3 September 2026

By Team GlobalCalqulate · About our editorial standards

What do you want to work out?

Calculation Type

Historical mode converts using the real published ONS index, so the answer is reproducible. Projection mode is for the future, where no index exists yet.

Amount to Adjust

Original Amount

Inflation Period

Start Year

Official ONS CPI annual averages are available from 1988 to 2025.

End Year

Official CPI runs to 2025. Later years are available for projection mode only — 2026 has no annual average yet because the year is still in progress.

How this estimate was calculated

Calculated as £100 × (138.4 ÷ 67.2) using the ONS Consumer Prices Index (series D7BT, 2015=100).
In other words, £100 in 1995 buys less than £205.95 in 2025 — the same basket of goods costs that much more.
CPI measures a representative basket of household goods and services. Your own inflation rate differs if your spending is weighted differently — housing, energy and childcare have all moved at very different rates from the headline index.
CPI is not RPI. RPI includes mortgage interest and council tax and typically runs higher; it was de-designated as a National Statistic in 2013.

Financial Disclaimer: Historical figures come from the ONS Consumer Prices Index and describe average price changes across a representative basket, not your own cost of living. Projections rely on an assumed rate you choose and are illustrations, not forecasts. Full disclaimer.

Sources & methodology

Formula:: Historical conversion (from the published CPI series)
Reference:: Office for National Statistics
Rates for:: 2025/26
Figures verified:: August 2026 — checked against the primary source above
Scheduled re-verification:: February 2027

Calculation type: Projection from your assumptions. Uses 2025/26 rates and thresholds. Figures are taken from Office for National Statistics — see sources below.

Reviewed by Team GlobalCalqulate — Verifies each figure against the issuing authority's published source · Checked 29 August 2026

Your entries stay on this device. This calculator runs entirely in your browser — the figures you type are not sent to us or to anyone else. The page itself uses cookies for analytics and advertising, described in the privacy policy.

Formula & methodology

Formula used

Historical conversion (from the published CPI series)

Adjusted = amount × (CPI_end ÷ CPI_start)

Two published index values are compared as a ratio. Because it is a ratio, the index base year cancels out and has no effect on the answer.

Total price change

Change % = (CPI_end ÷ CPI_start − 1) × 100

How much prices rose in total between the two years — not an annual rate.

Future projection (a rate you choose)

Future value = amount × (1 + r)^n

Compounds an assumed inflation rate forward. There is no index for the future, so this depends entirely on the rate you supply.

Variable definitions

Symbol	Meaning	Unit
CPI	Consumer Prices Index. The ONS all-items CPI (series D7BT, 2015 = 100), covering 1988 onwards.	index
amount	Starting amount. The sum of money being converted or projected.	£
r	Assumed annual inflation rate. Used only in projection mode, where no published index exists.	% per year
n	Number of years. The period over which the assumed rate compounds.	years

Step-by-step calculation

1. Choose the question being asked
Historical mode converts between two past years using real published data. Projection mode compounds an assumed rate into the future.
2. Look up both index values
In historical mode the calculator reads the annual average CPI for the start and end years from the ONS series.
3. Take the ratio
Multiplying by CPI_end ÷ CPI_start restates the amount in the later year's prices.
4. Or compound the assumed rate
In projection mode the amount is grown by (1 + r) once per year.

Limitations

CPI measures a representative basket of goods and services. Your personal inflation rate differs if your spending is weighted differently — housing, energy and food have all moved very differently from the headline rate.
The published series here starts in 1988. Conversions before that year are not available from this dataset.
CPI excludes owner-occupier housing costs; CPIH includes them and can tell a different story for homeowners.
Projection mode is an assumption, not a forecast. Nobody knows future inflation, and a constant rate is not how inflation actually behaves.
Annual average index values are used, so a conversion is year-to-year rather than to a specific month.
Wage growth is not modelled — an amount holding its real value is not the same as a salary keeping pace with the market.

This page is educational. It projects a future value from assumptions you choose, and a projection is not a forecast: real returns vary year to year, and the rules, limits and rates used here can change before the period modelled ends. Treat the output as one scenario among many, not a prediction of what you will have.

Sources & references

CPI INDEX 00: ALL ITEMS 2015=100 (series D7BT) — Office for National Statistics
Consumer price inflation, UK: July 2026 — Office for National Statistics

Help & FAQs

Frequently Asked Questions

Clear answers to common questions to help you use this calculator confidently.

How much will £1,000 be worth in 10 years?

Tap to view the answer

Enter £1,000, choose an inflation rate, and set the time horizon to estimate the future value or buying power. Testing low, base, and high inflation scenarios shows why prices rise over time and how much it matters.

What inflation rate should I use?

Tap to view the answer

There's no single perfect number, because inflation changes year to year and differs by category — food, rent, energy. Using several rates to stress-test your plan is smarter than picking one, and the comparison is quick here.

What are the most common mistakes people make about inflation?

Tap to view the answer

A major one is underestimating how inflation compounds over long periods. Another is planning savings goals using today's prices without adjusting for rising costs. Seeing the long-term effect helps you avoid both traps.

How does Office for National Statistics (ONS) CPI data relate to these estimates?

Tap to view the answer

ONS CPI data is a common framework for measuring price changes across the UK economy. This tool uses inflation logic similar to CPI-style adjustments, but it isn't an official ONS product, so refer to official sources for published inflation figures.

How do Bank of England policies influence inflation?

Tap to view the answer

Bank of England interest rate decisions can influence demand, borrowing costs, and inflation trends over time. The calculator doesn't forecast policy outcomes, but it lets you model different inflation scenarios — updating yearly keeps projections aligned with reality.

Need more help? Contact support or email globalcalqulate@gmail.com

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How to Use This Calculator

Enter Original Amount

Enter the amount of money you want to adjust for inflation.

Select Start Year

Choose the year when the money originally applied.

Select End Year

Choose the year you want to adjust the value to.

View Inflation-Adjusted Value

See what the money is worth today or in a future year after inflation.

Key Tips

✓
Compare With Savings Rate: If your savings interest is below inflation, your money is losing real value.
✓
Use for Salary Planning: Check how much salary increases need to beat inflation.
✓
Long-Term Planning: Inflation has a major impact on retirement and long-term goals.
✓
Review Regularly: Inflation changes yearly. Update calculations when new data is released.
✓
Check the Index Values, Not Just the Answer: Historical mode shows the two ONS index numbers it divided. You can verify any result against the ONS D7BT series yourself — if the two index values match, the answer is right.

How this calculator works, and what the numbers mean

The calculation is a ratio, not a compounded rate

Historical mode does not compound an average rate. It divides the ONS CPI index for your end year by the index for your start year and multiplies your amount by the result. Because the index is published, this is fully reproducible: £100 from 1995 (index 67.2) in 2025 money (index 138.4) is £100 x (138.4 / 67.2) = £205.95. The 'average annual inflation' figure shown alongside is derived from that ratio afterwards — it is the constant rate that would produce the same total change — and is never used to compute the answer itself.

Why the base year is 100, and why that means nothing

The ONS series is set to 2015 = 100. That is a labelling convention, not an economic statement: 2014 also reads 100.0 because of rounding, which does not mean prices were flat between them. Only the ratio between two years carries meaning, which is why this calculator never presents the base year as a reference point or a starting value.

CPI and RPI are different numbers, and the gap is not small

RPI includes mortgage interest payments and council tax, which CPI excludes, and it aggregates prices using an arithmetic formula rather than CPI's geometric one. That formula difference alone contributes a persistent wedge, and RPI typically prints higher than CPI. The ONS stripped RPI of its National Statistic designation in 2013 while it remains in use for index-linked gilts, some rail fares and student loan interest. Figures on this page are CPI only.

The headline rate is not your rate

CPI tracks a fixed representative basket, reweighted annually. Your personal inflation depends on what you actually buy: over the 2021-2023 period energy and food rose far faster than the headline index while some goods fell, so households with high energy shares experienced considerably more inflation than the published number. Treat the result as the change in the general price level, not as a personal cost-of-living figure.

Why the current year is missing from the dropdowns

An annual average requires twelve months of data. Until December is published there is no official annual figure for the current year, and averaging the months so far would produce a number the ONS does not publish and nobody could reproduce. The year is therefore omitted rather than estimated. Use projection mode if you need to model forward from today.

Formula & methodology

Formula used

Historical conversion (from the published CPI series)

Adjusted = amount × (CPI_end ÷ CPI_start)

Two published index values are compared as a ratio. Because it is a ratio, the index base year cancels out and has no effect on the answer.

Total price change

Change % = (CPI_end ÷ CPI_start − 1) × 100

How much prices rose in total between the two years — not an annual rate.

Future projection (a rate you choose)

Future value = amount × (1 + r)^n

Compounds an assumed inflation rate forward. There is no index for the future, so this depends entirely on the rate you supply.

Variable definitions

Symbol	Meaning	Unit
CPI	Consumer Prices Index. The ONS all-items CPI (series D7BT, 2015 = 100), covering 1988 onwards.	index
amount	Starting amount. The sum of money being converted or projected.	£
r	Assumed annual inflation rate. Used only in projection mode, where no published index exists.	% per year
n	Number of years. The period over which the assumed rate compounds.	years

Step-by-step calculation

1. Choose the question being asked
Historical mode converts between two past years using real published data. Projection mode compounds an assumed rate into the future.
2. Look up both index values
In historical mode the calculator reads the annual average CPI for the start and end years from the ONS series.
3. Take the ratio
Multiplying by CPI_end ÷ CPI_start restates the amount in the later year's prices.
4. Or compound the assumed rate
In projection mode the amount is grown by (1 + r) once per year.

Limitations

CPI measures a representative basket of goods and services. Your personal inflation rate differs if your spending is weighted differently — housing, energy and food have all moved very differently from the headline rate.
The published series here starts in 1988. Conversions before that year are not available from this dataset.
CPI excludes owner-occupier housing costs; CPIH includes them and can tell a different story for homeowners.
Projection mode is an assumption, not a forecast. Nobody knows future inflation, and a constant rate is not how inflation actually behaves.
Annual average index values are used, so a conversion is year-to-year rather than to a specific month.
Wage growth is not modelled — an amount holding its real value is not the same as a salary keeping pace with the market.

Calculator inputs

What do you want to work out?

Amount to Adjust

Inflation Period

Your results

Sources & methodology

Formula & methodology

Formula used

Historical conversion (from the published CPI series)

Total price change

Future projection (a rate you choose)

Variable definitions

Step-by-step calculation

Limitations

Sources & references

How much will £1,000 be worth in 10 years?

What inflation rate should I use?

What are the most common mistakes people make about inflation?

How does Office for National Statistics (ONS) CPI data relate to these estimates?

How do Bank of England policies influence inflation?

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Calculator inputs

What do you want to work out?

Amount to Adjust

Inflation Period

Your results

Sources & methodology

How to Use This Calculator

Worked example — £10,000 from 2010 in 2025 money

Understanding Your Results

Key Tips

How this calculator works, and what the numbers mean

The calculation is a ratio, not a compounded rate

Why the base year is 100, and why that means nothing

CPI and RPI are different numbers, and the gap is not small

The headline rate is not your rate

Why the current year is missing from the dropdowns

Formula & methodology

Formula used

Historical conversion (from the published CPI series)

Total price change

Future projection (a rate you choose)

Variable definitions

Step-by-step calculation

Limitations

Sources & references

How to Use This Calculator

Worked example — £10,000 from 2010 in 2025 money

Understanding Your Results

Key Tips

How this calculator works, and what the numbers mean

The calculation is a ratio, not a compounded rate

Why the base year is 100, and why that means nothing

CPI and RPI are different numbers, and the gap is not small

The headline rate is not your rate

Why the current year is missing from the dropdowns