About the Inflation Calculator
Inflation makes the same money buy less each year. This calculator has four views. Future cost shows what something that costs a given amount today will cost after a number of years at an inflation rate you choose. Buying power shows what an amount will be worth in today's terms. Find the rate works out the average yearly inflation between two prices. Price index (CPI) adjusts an amount using two index values that you type in. It applies the same rate every year and has no built-in inflation data, so it cannot tell you the real inflation of a past year. Real prices vary by item, such as food, rent or education, and from year to year, so treat the results as estimates.
Updated September 2026
How to use the Inflation Calculator
- 1Choose Future cost, Buying power, Find the rate or Price index (CPI).
- 2Enter the amount, the yearly inflation rate and the number of years.
- 3For the rate, enter the price then, the price now and the years between.
- 4For a price index, type both index values from an official source.
- 5Read the answer and the year-by-year table, then press Copy summary.
How inflation erodes money
When prices rise, each unit of currency buys less. Cash kept under a mattress, or in an account that pays less than inflation, loses buying power even though the number stays the same. At 3 percent a year, prices roughly double in 24 years, so a sum that seems comfortable today may be worth about half in a generation.
Future cost vs buying power
These two views are opposite sides of one calculation. Future cost asks how much you will need later to buy what costs a given amount now, so it multiplies. Buying power asks what a fixed amount will be worth later in today's terms, so it divides by the same growth factor. If you plan a goal that is years away, such as college fees, use Future cost to set the target.
Finding your own inflation rate
The average hides the ups and downs between the two dates. It is the constant yearly rate that would give the same overall change.
- Write down what you paid for something years ago
- Note today's price for the same thing
- Enter both prices and the years between them
- Read the average yearly rate
Using a price index
Official price indexes let you compare money across dates exactly. Look up the index for the year you start and the year you end, type them in, and the tool scales your amount by the ratio. Because index values differ by country and by basket, this page does not include them. To see how money grows with interest, use the Compound Interest Calculator, and for regular saving try the SIP Calculator. The Percentage Calculator handles one-off changes and the Discount Calculator handles sale prices.
Features
- Future cost after years of inflation
- Buying power in today's money
- Average yearly inflation between two prices
- Price index (CPI) adjustment using your own index values
- Year-by-year table up to 50 years
- Handles falling prices (negative inflation) down to −50%
- Currency symbol picker
- Runs in your browser
Frequently asked questions
How do I calculate the effect of inflation?
Multiply the amount by one plus the inflation rate, once for every year. At 3 percent, 100 becomes 103 after one year and about 134.39 after ten. Choose Future cost, enter the three numbers and read the result with a year-by-year table.
How much will 100 be worth in 10 years?
It depends on the rate. At 3 percent inflation, 100 will buy what about 74.41 buys today, so its buying power falls by roughly a quarter. Use the Buying power view and try different rates.
How do I find the average inflation rate between two prices?
Divide the new price by the old price, take the root that matches the number of years, and subtract one. A price rising from 100 to 150 over 10 years is an average of about 4.14 percent a year. Choose Find the rate and enter both prices.
What is a CPI and how do I use it?
A consumer price index tracks the cost of a typical basket of goods, and statistics offices publish it. To adjust an amount, multiply it by the index now and divide by the index then. Type both values into the Price index view, since this page does not store index data.
Why does my own inflation differ from the official one?
Official figures average a standard basket. Your own spending may lean toward rent, fuel, school fees or food, which can rise faster or slower than the average. Use Find the rate with prices you actually paid to see your own figure.
What inflation rate should I assume for planning?
Many planners use a long-run figure of 2 to 4 percent, but the right number depends on your country and on what you are saving for. Try a few rates on this page to see how sensitive your plan is.
Can inflation be negative?
Yes, falling prices are called deflation. This page accepts rates from −50 to 100 percent, and a negative rate makes future costs lower and buying power higher.