Results are estimates for guidance only and do not constitute financial advice. Always consult a qualified professional.
How to Use the Inflation Calculator
- Enter the amount — type the sum of money you want to adjust for inflation.
- Select the start year — choose the year the amount is from.
- Select the end year — choose the year you want to see the equivalent value in.
- Click "Calculate" — the calculator shows the equivalent value, total inflation rate, and average annual inflation between the two years.
- Try different periods — adjust the years to explore how inflation has affected purchasing power across different time spans.
How Inflation Calculation Works
This calculator uses the UK Consumer Price Index (CPI) to measure how prices have changed between any two years from 2000 to 2025. The CPI is compiled by the Office for National Statistics and tracks the average cost of a representative basket of goods and services purchased by UK households. To calculate the equivalent value of an amount from one year in another year, the calculator multiplies the original amount by the ratio of the CPI values for the two years: Equivalent Value = Amount x (CPI_end / CPI_start). The total inflation rate is the percentage increase between the two CPI values, and the average annual rate is derived using the compound annual growth rate formula. This method gives an accurate picture of how general price levels have changed, though individual goods and services may have experienced higher or lower inflation than the overall CPI figure.
What is inflation?
Inflation is the rate at which the general price level of goods and services rises over time, reducing the purchasing power of money. If inflation is 3% per year, something that costs £100 today would cost approximately £103 next year. Over longer periods, this effect compounds significantly.
What is the CPI?
The Consumer Price Index (CPI) measures the average change in prices paid by consumers for a basket of goods and services over time. The Office for National Statistics publishes UK CPI data monthly. It is the main measure used by the Bank of England for its 2% inflation target.
How is inflation calculated?
Inflation between two periods is calculated by comparing CPI index values: (CPI_end - CPI_start) / CPI_start x 100. To convert an amount from one year to another, multiply by CPI_end / CPI_start. This gives the equivalent purchasing power in the target year.
What has UK inflation been since 2000?
UK CPI has risen from an index of approximately 100 in 2000 to around 168 in 2025, meaning prices have increased by roughly 68% over 25 years. The steepest rises occurred between 2021 and 2023 due to energy price spikes and post-pandemic supply chain disruption.
What is the difference between CPI and RPI?
CPI and RPI both measure inflation but use different methodologies and baskets of goods. RPI includes housing costs like mortgage interest payments and council tax, while CPI does not. RPI typically runs 0.5 to 1 percentage point higher than CPI. CPI is the government's preferred inflation measure.
Why does inflation matter for savings?
If your savings earn less interest than the rate of inflation, your money loses purchasing power over time. For instance, if inflation is 5% and your savings earn 3%, you effectively lose 2% in real terms each year. Considering inflation is essential when planning long-term savings and investments.
