World War I & Armed forces mobilized and casualties

World War I, also called First World War or Great War, an international conflict that in 1914–18 embroiled most of the nations of Europe along with Russia, the United States, the Middle East, and other regions. The war pitted the Central Powers—mainly Germany, Austria-Hungary, and Turkey—against the Allies—mainly France, Great Britain, Russia, Italy, Japan, and, from 1917, the United States. It ended with the defeat of the Central Powers. The war was virtually unprecedented in the slaughter, carnage, and destruction it caused.

Armed forces mobilized and casualties in World War I*

*As reported by the U.S. War Department in February 1924. U.S. casualties as amended by the Statistical Services Center, Office of the Secretary of Defense, Nov. 7, 1957.
country	total mobilized forces	killed and died	wounded	prisoners and missing	total casualties	percentage of mobilized forces in casualties
Allied and Associated Powers
Russia	12,000,000	1,700,000	4,950,000	2,500,000	9,150,000	76.3
British Empire	8,904,467	908,371	2,090,212	191,652	3,190,235	35.8
France	8,410,000	1,357,800	4,266,000	537,000	6,160,800	73.3
Italy	5,615,000	650,000	947,000	600,000	2,197,000	39.1
United States	4,355,000	116,516	204,002	4,500	323,018	8.1
Japan	800,000	300	907	3	1,210	0.2
Romania	750,000	335,706	120,000	80,000	535,706	71.4
Serbia	707,343	45,000	133,148	152,958	331,106	46.8
Belgium	267,000	13,716	44,686	34,659	93,061	34.9
Greece	230,000	5,000	21,000	1,000	27,000	11.7
Portugal	100,000	7,222	13,751	12,318	33,291	33.3
Montenegro	50,000	3,000	10,000	7,000	20,000	40.0
total	42,188,810	5,142,631	12,800,706	4,121,090	22,064,427	52.3
Central Powers
Germany	11,000,000	1,773,700	4,216,058	1,152,800	7,142,558	64.9
Austria-Hungary	7,800,000	1,200,000	3,620,000	2,200,000	7,020,000	90.0
Turkey	2,850,000	325,000	400,000	250,000	975,000	34.2
Bulgaria	1,200,000	87,500	152,390	27,029	266,919	22.2
total	22,850,000	3,386,200	8,388,448	3,629,829	15,404,477	67.4
Grand total	65,038,810	8,528,831	21,189,154	7,750,919	37,468,904	57.5