U.S. inflation rate in 1909: -1.09%

Inflation in 1909 and its effect on dollar value

$1 in 1908 is equivalent in purchasing power to about $0.99 in 1909. The dollar had an average deflation rate of -1.09% per year since 1908, producing a cumulative price change of -1.09%. Purchasing power increased by 1.09% in 1909 compared to 1908. On average, you would have to spend 1.09% less money in 1909 than in 1908 for the same item. This is an example of deflation.

This means that prices in 1909 are 1.09% lower than average prices since 1908, according to the Bureau of Labor Statistics consumer price index.

The 1908 inflation rate was -2.13%. The inflation rate in 1909 was -1.09%. The 1909 inflation rate is lower compared to the average inflation rate of 3.08% per year between 1909 and 2021.

Inflation rate is calculated by change in the consumer price index (CPI). The CPI in 1909 was 9.10. It was 9.20 in the previous year, 1908. The difference in CPI between the years is used by the Bureau of Labor Statistics to officially determine inflation. Because the 1909 CPI is less than 1908 CPI, negative inflation (also known as deflation) has occurred.

Inflation from 1908 to 1909
Average inflation rate -1.09%
Converted amount ($1 base) $0.99
Price difference ($1 base) $-0.01
CPI in 1908 9.200
CPI in 1909 9.100
Inflation in 1908 -2.13%
Inflation in 1909 -1.09%
$1 in 1908 $0.99 in 1909

USD Inflation since 1635
Annual Rate, the Bureau of Labor Statistics CPI

Inflation by Country

Inflation can also vary widely by country. For comparison, in the UK £1.00 in 1908 would be equivalent to £1.01 in 1909, an absolute change of £0.01 and a cumulative change of 1.06%.

Compare these numbers to the US's overall absolute change of $-0.01 and total percent change of -1.09%.

Inflation by Spending Category

CPI is the weighted combination of many categories of spending that are tracked by the government. Breaking down these categories helps explain the main drivers behind price changes. This chart shows the average rate of inflation for select CPI categories between 1908 and 1909.

Compare these values to the overall average of -1.09% per year:

Category Avg Inflation (%) Total Inflation (%) $1 in 1908 → 1909
Food and beverages 0.00 0.00 1.00
Housing 0.00 0.00 1.00
Apparel 0.00 0.00 1.00
Transportation 0.00 0.00 1.00
Medical care 0.00 0.00 1.00
Recreation 0.00 0.00 1.00
Education and communication 0.00 0.00 1.00
Other goods and services 0.00 0.00 1.00

For all these visualizations, it's important to note that not all categories may have been tracked since 1908. This table and charts use the earliest available data for each category.

How to Calculate Inflation Rate for $1, 1908 to 1909

Our calculations use the following inflation rate formula to calculate the change in value between 1908 and 1909:

CPI in 1909 CPI in 1908
1908 USD value
1909 USD value

Then plug in historical CPI values. The U.S. CPI was 9.2 in the year 1908 and 9.1 in 1909:


$1 in 1908 has the same "purchasing power" or "buying power" as $0.99 in 1909.

To get the total inflation rate for the 1 years between 1908 and 1909, we use the following formula:

CPI in 1909 - CPI in 1908CPI in 1908
Cumulative inflation rate (1 years)

Plugging in the values to this equation, we get:

9.1 - 9.29.2

Comparison to S&P 500 Index

To help put this inflation into perspective, if we had invested $1 in the S&P 500 index in 1908, our investment would be nominally worth approximately $1.62 in 1909. This is a return on investment of 62.00%, with an absolute return of $0.62 on top of the original $1.

These numbers are not inflation adjusted, so they are considered nominal. In order to evaluate the real return on our investment, we must calculate the return with inflation taken into account.

The compounding effect of inflation would account for -1.10% of returns ($-0.02) during this period. This means the inflation-adjusted real return of our $1 investment is $0.64. You may also want to account for capital gains tax, which would take your real return down to around $1 for most people.

Investment in S&P 500 Index, 1908-1909
Original Amount Final Amount Change
Nominal $1 $1.62 62.00%
Inflation Adjusted
$1 $1.64 63.78%

Information displayed above may differ slightly from other S&P 500 calculators. Minor discrepancies can occur because we use the latest CPI data for inflation, annualized inflation numbers for previous years, and we compute S&P price and dividends from January of 1908 to latest available data for 1909 using average monthly close price.

For more details on the S&P 500 between 1908 and 1909, see the stock market returns calculator.

News headlines from 1908

Politics and news often influence economic performance. Here's what was happening at the time:

  • "Scouting for Boys", the book that became an inspiration for the Scout Movement, is published by Lieutenant General Robert Baden-Powell
  • King Carlos I of Portugal and his heir Prince Luis Filipe in Terreiro do Paco are assassinated.
  • A meteor explodes over Siberia with the power of several atomic bombs. This is known as the "Tunguska event".
  • The first Model T car is built.

Data Source & Citation

Raw data for these calculations comes from the Bureau of Labor Statistics' (CPI), established in 1913. Inflation data from 1665 to 1912 is sourced from a historical study conducted by political science professor Robert Sahr at Oregon State University.

You may use the following MLA citation for this page: “Inflation Rate in 1909 | Inflation Calculator.” Official Inflation Data, Alioth Finance, 28 Jul. 2021, https://www.officialdata.org/inflation-rate-in-1909.

Special thanks to QuickChart for their chart image API, which is used for chart downloads.

in2013dollars.com is a reference website maintained by the Official Data Foundation.

Ian Webster

About the author

Ian Webster is an engineer and data expert based in San Mateo, California. He has worked for Google, NASA, and consulted for governments around the world on data pipelines and data analysis. Disappointed by the lack of clear resources on the impacts of inflation on economic indicators, Ian believes this website serves as a valuable public tool. Ian earned his degree in Computer Science from Dartmouth College.

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» Read more about inflation and investment.

Inflation from 1908 to 1909
Average inflation rate -1.09%
Converted amount ($1 base) $0.99
Price difference ($1 base) $-0.01
CPI in 1908 9.200
CPI in 1909 9.100
Inflation in 1908 -2.13%
Inflation in 1909 -1.09%
$1 in 1908 $0.99 in 1909