Approximately 8 million military personnel were killed in action during World War I. Accurate figures are difficult to assess, and estimates can only approximate the actual number of fatalities.
Among the Allies, Russia had the heaviest battle fatalities, with 1.7 million dead. France lost 1.4 million combatants; the British Empire about 900,000; Italy 460,000; Romania 335,000; Portugal 100,000; the United States 50,000; Serbia 45,000; Belgium 13,500; Greece 5,000; Montenegro 3,000; and Japan about 300. A TOTAL of 4.8 million
Among the Central powers, Germany lost about 1.8 million battle dead; Austria 925,000; Turkey 325,000; and Bulgaria about 75,000. A TOTAL of 3.1 million
Russia lost more than 2 million civilians; Serbia about 650,000; Romania about 275,000; Greece about 132,000; France about 40,000; the British Empire 30,000; and Belgium 30,000. A TOTAL of 6.5 million
Of the Central Powers, Germany lost 760,000 civilians; Austria-Hungary 300,000; Bulgaria 275,000; and Turkey a staggering 2.1 million civilian dead. A TOTAL of 3.5 million