1918 (MCMXVIII) was a common year starting on Tuesday of the Gregorian calendar and a common year starting on Monday of the Julian calendar, the 1918th year of the Common Era (CE) and Anno Domini (AD) designations, the 918th year of the 2nd millennium, the 18th year of the 20th century, and the 9th year of the 1910s decade. As of the start of 1918, the Gregorian calendar was 13 days ahead of the Julian calendar, which remained in localized use until 1923.
The ceasefire that effectively ended the First World War took place on the eleventh hour of the eleventh day of the eleventh month of this year. Also in this year, the Spanish flu pandemic killed 50–100 million people worldwide.
In Russia, this year runs with only 352 days. As the result of Julian to Gregorian calendar switch, 13 days needed to be skipped. Wednesday, January 31 (Julian Calendar) was immediately followed by Thursday, February 14 (Gregorian Calendar).
World War I will be abbreviated as "WWI"
January – 1918 flu pandemic: The "Spanish flu" (influenza) is first observed in Haskell County, Kansas.
January 4 – The Finnish Declaration of Independence is recognized by Soviet Russia, Sweden, Germany and France.
January 8 – American president Woodrow Wilson presents the Fourteen Points as a basis for peace negotiations to end the war.
January 9 – Battle of Bear Valley: U.S. troops engage Yaqui Native American warriors in a minor skirmish in Arizona. This is one of the last battles of the American Indian Wars between the United States and Native Americans.
The keel of HMS Hermes is laid in Britain, the first purpose-designed aircraft carrier to be laid down.
The Red Army (The Workers and Peasants Red Army) is formed in the Russian SFSR and Soviet Union.
January 18 – The Historic Concert for the Benefit of Widows and Orphans of Austrian and Hungarian Soldiers is held at the Konzerthaus, Vienna.
January 19 – The Russian Constituent Assembly proclaims the Russian Democratic Federative Republic but is dissolved by the Bolshevik government on the same day.
January 22 – The Ukrainian People's Republic declares independence from Bolshevik Russia.
January 25 – The Third All-Russian Congress of Soviets establishes the Russian Soviet Federative Socialist Republic.
January 27 – The Finnish Civil War begins with the Battle of Kämärä.
January 28 – Porvenir massacre: Texas Rangers, U.S. Cavalry soldiers and local ranchers kill 15 unarmed Mexican villagers, both men and boys.
February 1 – Cattaro Mutiny: Austrian sailors in the Gulf of Cattaro (Kotor), led by two Czech Socialists, mutiny.
February 3 – Finnish Civil War: Battle of Oulu – The White Guard defeats the Reds.