1918 brought the steepest annual price increase the CPI had recorded: consumer prices rose 18.0% for the year, edging out 1917’s already sharp 17.4% as the economy stayed at full wartime mobilization for most of the year. A first-class stamp cost 3 cents, up from 2 cents the previous November under the War Revenue Act’s wartime tax increases. The war itself ended on November 11, when Germany signed an armistice with the Allied powers after more than four years of fighting in Europe, but the inflation built up over a year and a half of mobilization did not disappear along with the fighting. The bigger public health story that year was the influenza pandemic that reached the U.S. in a mild spring wave and then returned that fall in a far deadlier form, eventually killing roughly 675,000 Americans, more than the country’s combat losses in the war. It hit factories, docks, and shops alongside households, adding disruption to an economy already strained by wartime demand. Prices would keep climbing even after the armistice, into the postwar surge of 1919.
Year in review
Inflation in 1918
The U.S. inflation rate in 1918 was 18.0% (CPI: 15.1). Convert 1918 dollars to today →
18.0% 1918 inflation rate
10.0% 1910s average
20.7% peak month (Nov)
12.7% lowest month (Apr)
What things cost in 1918
| First-class stamp | $0.03 |
|---|
What $100 from 1918 was worth later
| In 1920 | $132 |
|---|---|
| In 1930 | $111 |
| In 1940 | $92.72 |
| In 1950 | $160 |
| In 1960 | $196 |
| In 1970 | $257 |
| In 1980 | $546 |
| In 1990 | $866 |
| In 2000 | $1,140 |
| In 2010 | $1,444 |
| In 2020 | $1,714 |
| In 2026 | $2,196 |
Inflation in 1918, month by month
| Month | CPI-U | 12-month rate |
|---|---|---|
| January | 14 | 19.7% |
| February | 14.1 | 17.5% |
| March | 14 | 16.7% |
| April | 14.2 | 12.7% |
| May | 14.5 | 13.3% |
| June | 14.7 | 13.1% |
| July | 15.1 | 18.0% |
| August | 15.4 | 18.5% |
| September | 15.7 | 18.0% |
| October | 16 | 18.5% |
| November | 16.3 | 20.7% |
| December | 16.5 | 20.4% |
Economic events of 1918
- Consumer prices rise 18.0% for the year, the fastest on record Wartime demand, an economy running at full military mobilization, and continued labor shortages pushed 1918's annual increase past 1917's already steep 17.4%, the highest rate in the CPI's history to that point.
- The influenza pandemic reaches the United States What became known as the Spanish flu arrived in a first wave in the spring, then returned far more lethal that fall and into 1919. It killed roughly 675,000 Americans, more than U.S. combat deaths in the war itself, and disrupted factories, shipping, and daily commerce across the country even as wartime production continued.
- World War I fighting ends with the Armistice Fighting stopped at 11 a.m. on November 11, 1918, when Germany signed an armistice with the Allied powers. The formal peace treaty was still months away, and wartime price pressures, built up over more than a year of full mobilization, did not ease immediately with the guns.
Sources: USPS historical postage rates; U.S. Bureau of Labor Statistics, Consumer Price Index history.
Inflation figures: U.S. Bureau of Labor Statistics, CPI-U annual averages. See the methodology.