Inflation Calculator

$100 in 2000 is worth $195.67 in September 2026

An inflation adjustment calculator converts an amount from one year into the money of another year, so you can see how much it takes to buy the same things. Using the Consumer Price Index for All Urban Consumers (CPI-U), the 2000 annual average is 172.2 and the September 2026 index is 336.94. Prices rose 95.7% in between, so $100 in 2000 has the same buying power as $195.67 today, an average of 2.59% a year. Turn it around and $100 today buys only what $51.11 bought in 2000, a 48.9% loss of buying power.

The calculator works in two ways. The actual prices mode uses annual averages from 1913 to 2025 plus the latest published month to move money between any two points in time. The assumed inflation rate mode takes a yearly rate you choose and finds either the money you will need in the future or what future money is worth today. Below you will find when the calculation is useful, how it works, a table by decade, the years with the biggest price changes, why the CPI can differ from what you feel, how to choose a rate for the future, common mistakes and the limits of the tool.

When you need to adjust for inflation

A dollar buys less each year, so dollar amounts from different years cannot be compared directly. If you want to compare a parent's salary, an old tuition bill, a past rent payment or a sum you lent years ago with today's figures, first move both to the same year. A $20 grocery trip in 1970, for example, would cost $173.68 in September 2026. A lot of the feeling that things used to be cheap is simply this price difference.

The same math supports planning. If prices rise 2% a year, what $100,000 buys today will cost $121,899.44 in 10 years, and $100,000 received in 10 years is worth $82,034.83 in today's money. When you judge a raise or a savings rate, check whether it beats inflation, because only then has your real position improved.

How the calculation works

1. Choose actual prices or an assumed inflation rate.
2. Enter an amount in dollars. Commas are added as you type, and cents are accepted.
3. In actual prices mode, pick the starting point (money then) and the point to compare with (money now). A year means the average of its twelve monthly indexes. The top option is the latest month published by the Bureau of Labor Statistics (BLS). The swap button in the middle reverses the direction.
4. In assumed rate mode, enter a yearly rate and a number of years, then choose whether to find the money needed in the future or the present value of future money.
5. The large figure is the equivalent amount. Two bars compare the size of the two amounts, and the rows below show the price change in between, the average yearly rate, the change in buying power and the conversion multiplier. The chart shows the equivalent value over time as a line and each year's inflation as bars. Tapping a decade tile makes that year the comparison point.

The formula is equivalent value = amount × index at the comparison point ÷ index at the starting point. For $100 in 2000, 100 × 336.94 ÷ 172.2 = $195.67. The average yearly rate compounds the ratio of the two indexes over the length of the period. Annual averages are placed in the middle of the year and the latest month in the middle of its month, so 2000 to September 2026 is about 26.2 years and the yearly rate is 2.59%.

The series is the CPI-U for the U.S. city average, all items, not seasonally adjusted, with 1982-84 set to 100. BLS describes the CPI-U population as over 90 percent of the U.S. population. The calculator uses only the ratio between two indexes, so the base period does not affect the result. BLS publishes its own CPI Inflation Calculator, which uses the same all-items, not seasonally adjusted series.

What $100 was worth, decade by decade

The table shows what $100 in each year equals in September 2026 money, the average yearly inflation over that period, and what $100 today would have been worth in that year. $100 in 1913 equals $3,403.43 today, while $100 today corresponds to only $2.94 in 1913 money.

The yearly rate for recent years looks high because the span is short and includes the rise in prices from 2021 on, and because the latest month is compared with an annual average that sits in the middle of 2025. Over long spans the average has stayed between roughly 2.6% and 3.9% a year.

Years of high and low inflation

A year's inflation here is its annual average index divided by the previous year's average. The highest in the series is 1918 at 18.0%, followed by 1917, 1920 and 1919. After World War II, 1947 reached 14.4%. The Federal Reserve's history of the Great Inflation, which it dates from 1965 to 1982, notes that an Arab oil embargo from October 1973 quadrupled crude oil prices and that the Iranian revolution in 1979 tripled their cost. In this data 1974 is 11.0%, 1979 is 11.3% and 1980 is 13.5%, the highest since 1947. More recently 2022 reached 8.0%, the highest since 1981. In the other direction, the annual average fell in 1921 and in the early 1930s, and in 2009 it dipped 0.4%, the first fall since 1955.

The bars under the calculator's chart show these values. The bars between your two chosen points are darker, and the highest year in that range is labeled. Two spans of the same length can give very different totals depending on which years they cover.

Why your own inflation can feel different

• It is an average basket: the CPI weights items by the average spending of urban households. If rent, gasoline or child care takes a bigger share of your budget, you feel those price changes more than the index does.
• Frequent purchases stand out: you see grocery and gas prices every week but notice less when electronics or phone plans get cheaper.
• Owned homes are counted as rent: BLS does not price houses themselves, because buying a home is treated as investment, not consumption. Instead it measures owners' equivalent rent, the rent an owner would have to pay to live in the home. That item is about a quarter of the CPI market basket (25.230 relative importance in December 2025). Stocks, bonds and real estate prices are not in the CPI.
• Substitution and quality changes: since 1999 the CPI has used a geometric mean formula that allows some substitution within item categories, and BLS notes that the CPI is only a conditional cost-of-living index.

Assuming a rate for the future

Nobody knows future inflation, so the assumed rate mode uses a number you choose. A common reference is the Federal Reserve's goal of 2% inflation over the longer run. The Fed measures it by the annual change in the price index for personal consumption expenditures (PCE), not the CPI, so the two are related but not identical. The table shows $100,000 at 2% and 3%.

The rule of 72 estimates the time for buying power to halve: 72 divided by the yearly rate. At 2% that is 36 years, while the exact figure is 35.0 years. At 3% the rule gives 24 years and the exact figure is 23.4. The calculator shows the exact number.

Common mistakes

• Dividing the total by the number of years: 95.7% over 26.2 years is not 3.7% a year. Prices compound, so the average is 2.59%.
• Mixing annual averages with monthly changes: the "12-month change" in the monthly news release compares one month with the same month a year earlier. The annual figures here compare yearly averages, so the two can differ for the same year.
• Treating the latest month and a year alike: a year is the average of twelve months, while the latest option is a single month. Comparing with September 2026 gives money of that month, and comparing with 2025 gives money of the 2025 average.
• Reading price adjustment as an income comparison: if wages rose faster than prices over a period, what a day of work buys has grown. The CPI adjustment compares prices only.
• Expecting one rate to fit everyone: a single national index cannot capture your region or your spending mix.

Limits

• Only one national index is used, the CPI-U for the U.S. city average. Regional, item level and household differences are not reflected.
• Years are annual averages and 2026 offers only the latest month. For a comparison between two specific months, use the BLS CPI Inflation Calculator.
• Taxes, interest and investment returns are not included.
• The result is an estimate from a price index. It is not a legal basis for damages, contracts or settlements.
• The assumed rate mode repeats the same percentage every year, while real inflation moves up and down.

As of The figures were checked on 2026-10-16 against BLS CPI-U data (U.S. city average, all items, not seasonally adjusted, 1982-84=100). Annual averages cover 1913 to 2025 and the latest month is September 2026 (336.94). The table values come from this calculator, and assumed rates such as 2% and 3% are examples, not forecasts.

Sources

• 01U.S. Bureau of Labor Statistics: Consumer Price IndexSeptember 2026 index published October 14, 2026, up 3.7% over the year
• 02BLS: Consumer Price Index questions and answersCPI-U covers over 90 percent of the population, 1982-84=100, stocks, bonds and real estate are excluded
• 03BLS: Owners' equivalent rent and rentHome purchases are treated as investment, owners' equivalent rent is included in shelter
• 04BLS: CPI Inflation CalculatorOfficial calculator based on CPI-U, U.S. city average, all items, not seasonally adjusted
• 05Federal Reserve: What is the Fed's inflation goal?2 percent over the longer run, measured by the PCE price index
• 06Federal Reserve History: The Great Inflation1965 to 1982, oil shocks of 1973 and 1979

Frequently asked questions

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