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UK Inflation Calculator

Estimate how much you would need in future to match today's buying power, using an annual inflation rate you choose. This models a constant rate; it does not look up historical CPI between two dates.

Tool
£—

Your money

£
%

Latest UK CPI: 3.1% (August 2026, ONS). The Bank of England targets 2%.

10 years
No sign-up · No tracking · Runs in your browser
Same buying power in 10 years Constant-rate estimate

£—
Future value loses purchasing power£—
Cumulative inflation£—
£10,000 today would buy the same as £— of today's money if prices rose 3.1% a year for 10 years.
Inflation erodes the real value of cash — a constant 3.1% is an assumption, not a forecast.

Data: ONS — Consumer price inflation (CPI 3.1%, August 2026) · Bank of England — 2% target.

How it works

Inflation means the same amount of money buys less over time. The calculator shows the future nominal amount you would need to keep the same buying power, how much a future sum is worth in today's money, and the cumulative inflation over the period.

Example calculation

With £10,000 today, 3.1% annual inflation over 10 years:

  • Future nominal amount needed: ≈ £13,570
  • So £10,000 in 10 years would buy what ≈ £7,369 buys today
  • Cumulative inflation: ≈ 35.7%

Example is illustrative. CPI inflation changes every month; 3.1% is the August 2026 rate.

Methodology & formula

Annual compounding, the same growth formula used across the site:

Future nominal = A × (1 + r)n
Today's value of a future amount = A ÷ (1 + r)n
  • A = amount
  • r = annual inflation rate (as a decimal)
  • n = number of years

Assumption: a constant inflation rate each year. Real inflation varies from year to year, so this is a planning estimate.

UK-specific information

  • CPI: the headline UK inflation measure, 3.1% in the 12 months to August 2026. ONS · Aug 2026
  • CPIH: CPI including owner-occupier housing costs — the ONS's preferred measure, 3.3% in August 2026.
  • Bank of England target: the BoE aims for CPI inflation of 2% — the rate to think of for long-run planning. BoE
  • RPI: a legacy UK inflation measure. It is not an accredited official statistic, but ONS still publishes it monthly; RPI inflation was 3.4% in August 2026. CPIH methods and data sources are due to be introduced into RPI from 2030 at the earliest.
  • State Pension: the triple lock raises it in line with inflation, wage growth or 2.5%, whichever is highest — so it tends to keep pace with rising prices.

Frequently asked questions

What is CPI inflation?
The Consumer Prices Index measures how the price of a typical basket of goods and services changes over 12 months. It is the UK's headline measure of inflation.
What inflation rate should I use?
For long-term planning, 2% (the Bank of England target) is a common choice. The latest CPI rate is 3.1% (August 2026). You can adjust the rate to your own view.
Why does cash lose value with inflation?
If prices rise 3.1% a year, £100 today buys what £103.10 buys in a year — your cash buys less. Savings only beat inflation if they earn more than the inflation rate.
Does this calculator forecast inflation?
No. It shows the maths of a constant rate you choose. Actual inflation varies each year and cannot be reliably predicted.
What is the difference between CPI and RPI?
CPI is the headline measure. RPI is a legacy measure that is not an accredited official statistic, though ONS still publishes it and some index-linked contracts continue to reference it.
How does inflation affect my savings and pension?
Inflation reduces what your savings and pension buy in retirement. The Retirement and Pension calculators help you plan in today's money, so you can see the real target.

Related calculators

How does inflation affect your money? · UK Savings Calculator · Compound Interest Calculator · Pension Calculator · Home

Sources

Casvia provides educational calculators and general information. It does not provide personal financial, tax or investment advice. Inflation figures change monthly — always check the latest ONS release.