Two different questions
If a basket costs £100 today, a hypothetical 10% annual price rise makes it cost £110 after one year. A fixed £100 would then have about £90.91 of today’s buying power. A fall in prices reverses that relationship. These are made-up examples, not current UK inflation figures.
The Bank of England explains inflation through changes in the prices of a basket of goods and services. Your own spending mix may experience different changes. This tool uses one fixed annual assumption for everything.
How the calculation works
Price factor = (1 + annual inflation ÷ 100) raised to the number of years. Future basket cost = today’s amount × price factor. Buying power of the fixed amount, in today’s pounds = today’s amount ÷ price factor. Zero years or zero inflation leave both amounts unchanged.
No interest, investment returns, fees, contributions, withdrawals, tax, income changes or scheme increases are included. This does not estimate a pension pot, defined benefit income, State Pension, an annuity or how much you should save. Rates and prices can vary each year; actual outcomes will differ. Input limits keep the tool bounded and do not imply realistic forecasts. General information, not financial advice.
Inputs and results stay in this page’s memory. They are not sent to a server, added to the URL or saved in browser storage. Reloading clears them. Optional local calculator events contain only the tool path and event name, never amounts or rates; no analytics provider is connected.
Source and model checks
Concept source and model checked 2026-10-04. Next scheduled review: 2027-04-04. Source checking does not claim a qualified financial review.
For historical UK prices, use the Bank of England’s historical inflation calculator. Our tool uses your assumed rate rather than historical data.
Keep pension figures in context
Illustrate growth and monthly additions separately →