CalculatorsSwitch calculator
How this works
Inflation is how fast prices rise. The calculator grows an amount by the inflation rate each year to show what the same things could cost in future. It also runs the sum the other way to show what the same cash would buy in today’s prices if it sat still.
If you add a savings rate, it works out your real return, what your savings grow by once rising prices are taken into account.
What it assumes
- Inflation is the same every year. In real life it changes, and some things rise faster than others.
- Tax on interest isn’t included.
- The starting inflation rate is UK CPI of 3.1%, as of October 2026.
Worked example
£1,000 at 3.1% inflation
- Things that cost £1,000 today could cost £1,357.02 in 10 years.
- Left in cash earning nothing, £1,000 would buy only £736.91 of today’s shopping after 10 years. That’s about a quarter of its value gone.
- After 20 years the same £1,000 buys £543.03 worth.
- In an account paying 4%, your real return is about 0.87% a year. You’re still ahead, just by much less than the headline rate.
Worked out with the same maths as the calculator above.
What to do next
Common questions
Which inflation rate should I use?
CPI is the official measure and the one the Bank of England targets. The government has set it a target of 2%. For long periods, people often try somewhere between 2% and 3%.
Why not just take inflation away from my interest rate?
That’s close, but slightly off. The accurate real return is (1 + interest rate) ÷ (1 + inflation) − 1. At 4% interest and 3.1% inflation that’s 0.87%, not 0.9%.
Does inflation affect debts too?
Yes, in your favour. A fixed debt, such as a fixed-rate mortgage balance, is worth less in real terms as prices and usually wages rise.
How can I protect savings from inflation?
Keep emergency money in the best easy-access rate you can find. For money you won’t need for five years or more, investing has historically beaten inflation more often than cash, though with ups and downs.