Inflation Calculator
See what prices will be in the future, how much your money will really buy, and what an old amount is worth today. You enter the inflation rate, so it works for any country.
Look up your country's consumer price index (CPI) for both dates on its statistics office or central bank website. Any base year works, as long as both numbers come from the same series.
One rate per year, separated by commas or spaces. Use a minus sign for falling prices.
Year-by-year table and chart
How your inflation sum is worked out
Prices grow like compound interest: amount × (1 + rate)^years.
- 1
Growth each year
1 + 5%= 1.05
- 2
Over the years
1.05^10= 1.6289
- 3
Future cost
1,000 × 1.6289= 1,629
- 4
Buying power lost
1 − 1 ÷ 1.6289= 38.6%
Read more: the formula, a worked example, real returns and price indexes
Inflation is how fast prices rise. When prices rise, the same money buys less. Inflation works like compound interest: each year's rise is added on top of the last one, so 5% a year for 10 years raises prices by about 63%, not 50%.
The formula
future cost = price today × (1 + inflation rate)^years
buying power = money today ÷ (1 + inflation rate)^years
value from a price index = amount × index at the end ÷ index at the start
average inflation = (later price ÷ earlier price)^(1 ÷ years) − 1
real return = (1 + your return) ÷ (1 + inflation) − 1
Write rates as decimals in the formulas: 5% is 0.05. When the rate changes each year, multiply the yearly factors instead: (1 + rate in year 1) × (1 + rate in year 2) × …
Worked example
Something costs 1,000 today and prices rise 5% a year. Each year prices are multiplied by 1.05. Over 10 years that is 1.0510 = 1.6289, so it will cost 1,000 × 1.6289 = 1,628.89 (about 1,629). Prices have risen 62.89% in total. Turned the other way, 1,000 kept in cash buys only 1,000 ÷ 1.6289 = 613.91 worth of today's goods after 10 years, so it has lost 1 − 1 ÷ 1.6289 = 38.6% of its buying power.
Past value from a price index
Statistics offices publish a consumer price index (CPI): the cost of a typical basket of shopping, scaled so that one base year is 100. To find what an old amount is worth today, divide today's index by the old one and multiply. If the index was 100 then and 162.89 now, 1,000 then is worth 1,000 × 162.89 ÷ 100 = 1,628.89 now. Enter the number of years as well and the calculator shows the average rate: (1.6289)1/10 − 1 = 5% a year.
We don't include any country's price history, because we can't check it for every country. Use the official CPI from your own country's statistics office or central bank, and make sure both numbers come from the same series and base year.
Real return: did you beat inflation?
If your savings earn 8% a year and inflation is 5%, your real return is 1.08 ÷ 1.05 − 1 = 2.86% a year, a little less than the quick estimate of 8 − 5 = 3%. This is the Fisher equation. Tax on returns lowers it further: at 30% tax, 8% becomes 5.6%, and the real return is 1.056 ÷ 1.05 − 1 = 0.57%.
The salary you need to keep up
If you earned 50,000 five years ago and prices rose 4% a year, you need 50,000 × 1.045 = 60,833 now to buy the same things, a raise of 21.7%. If you now earn 55,000, your pay went up 10% but its buying power fell by 1 − 55,000 ÷ 60,833 = 9.6%.
How fast prices double
| Inflation a year | Prices double in | Money's value halves in |
|---|---|---|
| 2% | 35.0 years | 35.0 years |
| 3% | 23.4 years | 23.4 years |
| 5% | 14.2 years | 14.2 years |
| 7% | 10.2 years | 10.2 years |
| 10% | 7.3 years | 7.3 years |
Doubling time = log(2) ÷ log(1 + rate). The rule of 70 is a quick shortcut: 70 ÷ the rate. At 5%, 70 ÷ 5 = 14 years.
Your own costs can rise faster or slower than the official average, depending on what you buy: rent, school fees, fuel and food often move differently. The results assume the rates you enter; real inflation changes from year to year. Monthly rates are turned into yearly ones with compounding: 0.5% a month is (1.005)12 − 1 = 6.17% a year.
Common questions
How do you calculate inflation over several years?
Inflation compounds, so multiply the price by (1 + yearly rate) once for each year. At 5% a year for 10 years, 1.05 to the power of 10 is 1.6289, so something costing 1,000 today will cost about 1,629. Prices have risen about 63%, not 50%.
How much buying power does money lose to inflation?
Divide the money by (1 + inflation rate) raised to the number of years. At 5% a year, 1,000 kept in cash buys only about 614 worth of today's goods after 10 years, so it has lost 38.6% of its buying power.
How do I find what an old amount is worth today?
Use your country's consumer price index (CPI): multiply the old amount by today's index and divide by the index for the old year. If the index was 100 then and 162.89 now, 1,000 then is worth 1,628.89 now. Make sure both numbers come from the same series and base year.
What is a real return after inflation?
It's what your money really earns once inflation is taken out: (1 + your return) ÷ (1 + inflation) − 1. Earning 8% with 5% inflation is a real return of 2.86% a year, a little less than the quick estimate of 3%. Tax on returns lowers it further.
How fast do prices double with inflation?
For a quick answer, divide 70 by the yearly inflation rate (the rule of 70). At 5% inflation prices double in about 14 years, at 3% in 23.4 years and at 10% in 7.3 years. Your money's value halves in the same time.
How much of a pay rise do I need to keep up with inflation?
Multiply your old pay by (1 + inflation) once for each year since. If you earned 50,000 five years ago and prices rose 4% a year, you need 60,833 now to buy the same things, a raise of 21.7%. Anything less means your pay buys less than before.
Related calculators
Made by Zulu Calculator, part of AlphaZulu LLC. Formulas are shown in full and rule figures are checked against official sources; see how we build calculators.