Total World War 1 casualties were over 8.5 million.
| Countries | Killed & Died | Wounded | Prisoners & Missing |
| – Allied Powers – | |||
| Russia | 1,700,000 | 4,950,000 | 2,500,000 |
| France | 1,357,800 | 4,266,000 | 537,000 |
| British Empire | 908,371 | 2,090,212 | 191,652 |
| Italy | 650,000 | 947,000 | 600,000 |
| United States | 126,000 | 234,300 | 4,500 |
| Japan | 300 | 907 | 3 |
| Romania | 335,706 | 120,000 | 80,000 |
| Serbia | 45,000 | 133,148 | 152,958 |
| Belgium | 13,716 | 44,686 | 34,659 |
| Greece | 5,000 | 21,000 | 1,000 |
| Portugal | 7,222 | 13,751 | 12,318 |
| Montenegro | 3,000 | 10,000 | 7,000 |
| Total | 5,152,115 | 12,831,004 | 4,121,090 |
| – Central Powers – | |||
| Germany | 1,773,700 | 4,216,058 | 1,152,800 |
| Austria-Hungary | 1,200,000 | 3,620,000 | 2,200,000 |
| Turkey | 325,000 | 400,000 | 250,000 |
| Bulgaria | 87,500 | 152,390 | 27,029 |
| Total | 3,386,200 | 8,388,448 | 3,629,829 |
| Grand Total | 8,538,315 | 21,219,452 | 7,750,919 |