Inflation Calculator
See what money will cost, or be worth, after years of inflation.
Good to know. At 3% a year, prices roughly double in 24 years. That’s the rule of 72 again.
Not financial advice. Uses only the numbers and rates you enter — no live data.
How it works
In plain words
Prices grow by the inflation rate every year, and each year’s rise builds on the last, just like compound interest. To go back to today’s money, divide instead of multiply.
The formula
future cost = amount × (1 + rate ÷ 100)^years today’s value = amount ÷ (1 + rate ÷ 100)^years
Worked example
With 3% inflation a year, something that costs 100 today will cost 100 × 1.03¹⁰ = 134.39 in 10 years. Prices rise 34.39% in total.
Sources
- Brealey, Myers and Allen, Principles of Corporate Finance, chapter 2 The standard formulas for loan payments, compounding and present value, the same as a spreadsheet’s PMT and FV.
- US Bureau of Labor Statistics, Consumer Price Index Where to find the US inflation rate.
- Office for National Statistics, inflation and price indices Where to find the UK inflation rate.
Sources checked September 29, 2026. 5 automated tests check its answers on every change.
About the inflation calculator
Inflation is the gradual rise in prices over time, which means a fixed amount of money buys a little less every year. Over a year, it’s easy to ignore. Over ten or twenty years, it is hard to miss: at 3% a year, prices rise by a third in a decade and nearly double in 24 years.
This calculator works in two directions. "Future cost" tells you what something priced today is likely to cost later, which is useful for planning big expenses and long-term savings goals. "Worth today" turns a future amount into today’s money, which is useful for judging a pension projection or a salary offer years from now.
You choose the rate. We don’t use live or historical inflation data, because it varies by country and by year, and the right assumption depends on what you’re planning. Many central banks target around 2% a year. Recent years have seen much higher rates in many countries, so try a few values to see the range.
Individual prices don’t all rise at the official rate. Rent, energy, food and education can move faster or slower than the average, so your personal inflation rate may be different.
Questions people ask
How do I calculate the effect of inflation?
Multiply the amount by (1 + rate)^years. At 3% for 10 years, 100 becomes 100 × 1.03¹⁰ = 134.39.
What inflation rate should I use?
It is up to you. Many central banks aim for about 2%. For caution, try a higher rate too and compare.
How long does it take for prices to double?
About 72 divided by the inflation rate, in years. At 3%, roughly 24 years.
Does this use official inflation data?
No. It uses only the rate you enter, and assumes it stays the same every year.