Cumulative Inflation Calculator

Calculate How Inflation Changes the Value of Money Over Time

Use this Cumulative Inflation Calculator to see how purchasing power changes between two dates. Enter an amount and select the start and end dates (month and year) to instantly calculate cumulative inflation and determine what your money would be worth today.

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Calculate Cumulative Inflation to the Month and Year

We’ve updated and modernized our Cumulative Inflation Calculator. Using this Calculator, you can determine the total inflation (in percent) between any two (monthly) dates from 1913 to the present. It also tells you the inflation-adjusted price compared to the nominal price. This calculator uses the U.S.D. Consumer Price Index (CPI-U) published by the U.S. Bureau of Labor Statistics. The CPI-U is the most closely watched indicator for inflation in the U.S. It can be considered the “government’s key inflation barometer”. To start, you must enter an amount, then select the starting month and year and the ending month and year, and then click the “Calculate” button to see your inflation calculation.

Note: To get a full 12 months, you must have the same starting month and ending month. In other words, a full year is January to January, not January to December! Remember, the data is released mid-month for the prior month and is two weeks old by the time it is released by the Bureau of Labor Statistics. So, depending on what time of month it is, you can only get data up through last month or even the previous month. (Early in the month, you will have to go two months prior; late in the month, it will be the previous month.

Note: This U.S. Inflation Rate Calculator gives you the percentage of increase in prices over a period. For example, from January 2024 – January 2025, prices increased 3.00%. Therefore, something that cost $1 in January 2024 would cost $1 + (inflation rate) in January 2025. So in this case, it would be $1+($1 x .0300)= $1.0300 or $1.03.

Although this seems obvious for one year, when the inflation rate gets larger (above 100%) it is not so intuitive.

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How the Cumulative Inflation Calculator Works

Inflation measures how prices rise and purchasing power declines over time. This calculator applies official CPI data to compute the cumulative percentage increase between two years and adjusts your dollar amount accordingly.

You can see:

• Total cumulative inflation percentage
• Inflation-adjusted value
• Change in purchasing power
• Real value comparison between periods

For example, $100 in 1990 has significantly less buying power today due to decades of cumulative inflation.

Why Cumulative Inflation Matters

Looking at annual inflation alone doesn’t tell the full story. Cumulative inflation shows the total impact over many years — revealing how steadily rising prices erode savings, wages, and fixed incomes.

Understanding cumulative inflation helps you:

• Compare historical prices accurately
• Adjust past salaries for today’s dollars
• Evaluate long-term investment returns
• Measure real economic growth
• Understand cost-of-living changes

Even low yearly inflation compounds dramatically over time.

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Flat Rate Inflation Calculator

Common Uses

People use cumulative inflation calculators to:

• Convert past dollars into today’s value
• Analyze long-term purchasing power
• Compare historical housing prices
• Adjust retirement income
• Evaluate government spending in real terms
• Study economic trends

Sample Calculation:

From December 1957 through December 2007, the Inflation Rate Calculator will tell you that inflation was 639.56%. Remember, the result is in percent. To calculate its decimal equivalent, you need to move the decimal point two places to the left. So 639.56% = 6.3956 in decimals.

So we find that something that cost $1 in December 1957 would cost $1+ ($1 x 6.3956)=$7.40

Rather than doing the calculations yourself, if you already know the inflation rate but you want to know how much something would cost after increasing by that amount of inflation, simply plug the starting amount (without commas or decimals) into this calculator. Then, put in the inflation rate you want calculated and click calculate.

• If you don’t know what inflation rate to choose… the average U.S. inflation rate over long periods has been 3.16% (of course, that is for a single year).

How Much Would it Cost after Inflation Calculator

This calculator has three functions:

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The following Chart shows the cumulative inflation over previous decades since 1913, when the Bureau of Labor Statistics began tracking inflation.