Inflation Calculator

What this calculator does

Money does not hold still. A sum that bought a week of groceries decades ago would barely fill a bag today, and that slow slide is inflation at work. This calculator lets you measure it.

You enter an amount, a year it came from, and a year to compare it to, and it tells you what that money is worth in the second year, once inflation is accounted for. It is a way to put old prices, old salaries, and old savings into today's terms, so numbers from different years can finally be compared honestly.

How to use it

1. Amount. The sum of money you want to convert, in US dollars.
2. From year. The year the amount belongs to.
3. To year. The year you want its value expressed in.

Press Calculate and it shows what your amount from the first year is worth in the second. Press Reset to clear it. The years can run in either direction, so you can bring an old amount forward to today, or take a today amount back into the past.

Inflation, and what it does to money

Inflation is the gradual rise in the general level of prices over time. When prices go up, each unit of money buys a little less than it did before. That is the part that matters to you: not the prices themselves, but what your money can still do, which is called its purchasing power.

To measure this, economists track the price of a fixed basket of everyday goods and services, the kind of things a typical household actually buys, and watch how the cost of that basket changes year to year. That measure is the Consumer Price Index, or CPI. When the CPI doubles, it takes twice as much money to buy the same basket, which is another way of saying your money now buys half as much. This calculator uses the CPI to do its conversions.

How the conversion works

The method is a simple ratio. Each year has a CPI value, and the change in buying power between two years is just the ratio of their CPI values:

Value in the target year = amount × ( CPI of target year ÷ CPI of starting year )

So if prices, measured by the CPI, are three times higher in the later year, your amount is multiplied by three to keep the same buying power. That is the whole calculation. Its honesty rests entirely on the CPI figures behind it, which is why the next section is worth a look.

A worked example you can check

Say you want to know what $100 in 1990 is worth in 2024. The CPI stood at 130.7 in 1990 and 314.4 in 2024. Let us run it.

• CPI ratio: 314.4 ÷ 130.7 = about 2.41
• Value in 2024: 100 × 2.41 = 240.55

So $100 in 1990 has the same buying power as $240.55 in 2024. Put the other way, you would need almost two and a half times as much money today to match what a hundred dollars did back then. Go further back and the effect is striking: a single dollar from 1913, the earliest year here, is worth about $31.76 in 2024. That is a century of prices climbing, laid out in one number.

What these numbers are based on

It is only fair to be clear about what is under the hood, because it tells you exactly what this tool is for.

The figures come from the United States Consumer Price Index, specifically the index for All Urban Consumers, published by the US Bureau of Labor Statistics. Two things follow from that. First, this measures US dollars and US prices, so it is the right tool for dollar amounts, not for other currencies, which have their own inflation histories. Second, it uses one figure per year, the annual average, and covers 1913 through 2024. So it compares whole years rather than specific months, and those two years are the edges of what it can reach. Within that, it is grounded in the same official price data economists, courts, and government agencies rely on.

Questions people ask

What exactly is the CPI?

The Consumer Price Index tracks the average change over time in the prices paid by urban households for a basket of everyday goods and services. It is the standard yardstick for inflation, and the basis for the conversions here.

Can I use this for currencies other than dollars?

Not accurately. The data is the US Consumer Price Index, so the results hold for US dollars. Other countries have their own inflation records, and their money would have followed a different path.

Can it go backwards, from a recent year to an older one?

Yes. Put the recent year as the starting year and the older one as the target, and it shows what today's money would have been worth back then. The ratio simply flips.

Why is the same basket so much more expensive now?

Because prices have risen, year after year, for over a century. Small yearly increases compound into large gaps across decades, which is why an amount from long ago converts into so much more today.

References

The conversions use annual Consumer Price Index values for All Urban Consumers, published by the US Bureau of Labor Statistics, which defines the CPI as the measure of the average change over time in the prices paid by urban consumers for a basket of goods and services.

1. U.S. Bureau of Labor Statistics, Consumer Price Index. https://www.bls.gov/cpi/