Size of Forces
| Countries in First World War | Standing Armies & Reserves in August 1914 | Mobilized Forces in 1914-18 |
| Russia | 5,971,000 | 12,000,000 |
| France | 4,017,000 | 8,410,000 |
| Great Britain | 975,000 | 8,905,000 |
| Italy | 1,251,000 | 5,615,000 |
| United States | 200,000 | 4,355,000 |
| Japan | 800,000 | 800,000 |
| Romania | 290,000 | 750,000 |
| Serbia | 200,000 | 707,000 |
| Belgium | 117,000 | 267,000 |
| Greece | 230,000 | 230,000 |
| Portugal | 40,000 | 100,000 |
| Montenegro | 50,000 | 50,000 |
| Germany | 4,500,000 | 11,000,000 |
| Austria-Hungary | 3,000,000 | 7,800,000 |
| Turkey | 210,000 | 2,850,000 |
| Bulgaria | 280,000 | 1,200,000 |
Ships Lost
| Country | Battleships | Cruisers | Torpedo Boats | Submarines | Destroyers |
| Allied Powers | |||||
| Russia | 4 | 2 | 0 | 14 | 22 |
| France | 4 | 5 | 8 | 12 | 11 |
| Great Britain | 13 | 25 | 11 | 54 | 64 |
| Italy | 3 | 3 | 6 | 8 | 8 |
| United States | 0 | 3 | 0 | 1 | 2 |
| Japan | 1 | 4 | 1 | 0 | 2 |
| Central Powers | |||||
| Germany | 1 | 7 | 55 | 200 | 68 |
| Austria-Hungary | 3 | 2 | 4 | 7 | 4 |
| Turkey | 1 | 2 | 5 | 0 | 3 |
Financial Cost
| Allied Powers | Cost in Dollars in 1914-18 |
| United States | 22,625,253,000 |
| Great Britain | 35,334,012,000 |
| France | 24,265,583,000 |
| Russia | 22,293,950,000 |
| Italy | 12,413,998,000 |
| Belgium | 1,154,468,000 |
| Romania | 1,600,000,000 |
| Japan | 40,000,000 |
| Serbia | 399,400,000 |
| Greece | 270,000,000 |
| Canada | 1,665,576,000 |
| Australia | 1,423,208,000 |
| New Zealand | 378,750,000 |
| India | 601,279,000 |
| South Africa | 300,000,000 |
| British Colonies | 125,000,000 |
| Others | 500,000,000 |
| Total of all Costs | 125,690,477,000 |
Gas Casualties
| Country | Non-Fatal | Deaths | Total |
| British Empire | 180,597 | 8,109 | 188,706 |
| France | 182,000 | 8,000 | 190,000 |
| United States | 71,345 | 1,462 | 72,807 |
| Italy | 55,373 | 4,627 | 60,000 |
| Russia | 419,340 | 56,000 | 475,340 |
| Germany | 191,000 | 9,000 | 200,000 |
| Austria-Hungary | 97,000 | 3,000 | 100,000 |
| Others | 9,000 | 1,000 | 10.000 |
| Total | 1,205,655 | 91,198 | 1,296,853 |
American Casualties by Cause of Death
| Cause of Death | Overseas | Domestic | Total |
| Killed in Action | 36,926 | 5 | 36,931 |
| Died of Wounds | 13,628 | 45 | 13,673 |
| Died of Accident | 2,557 | 1,946 | 4,503 |
| Drowned | 328 | 399 | 727 |
| Committed Suicide | 296 | 671 | 967 |
| Murdered | 159 | 159 | 318 |
| Executed | 11 | 25 | 36 |
| Other Deaths | 131 | 190 | 321 |
| Total | 54,036 | 3,440 | 57,476 |
Aircraft Lost
| Country | Aircraft | Airships |
| Germany | 246 | 11 |
| Austria-Hungary | 35 | 1 |
| Britain | 110 | 6 |
| France | 160 | 4 |
| Russia | 300 | 11 |
| Belgium | 25 | – |