World War I casualties

thumb|upright=1.8|A graph showing the World War I military and civilian casualties by individual countries

The total number of military and civilian casualties in World War I is estimated to be 15 to 22 million deaths and about 21 million wounded military personnel, making it one of the deadliest military conflicts in human history.

The total number of deaths includes nine to 11 million military personnel. The civilian death toll was about six to 13 million. The Triple Entente (also known as the Allies) lost about six million military personnel while the Central Powers lost about four million. At least two million died from diseases and six million went missing, presumed dead. This article lists the casualties of the belligerent powers based on official published sources.

About two-thirds of military deaths in World War I were in battle, unlike the conflicts that took place in the 19th century when most deaths were from disease. Nevertheless, disease, including the 1918 flu pandemic and deaths while held as prisoners of war, still caused about one third of total military deaths for all belligerents.

Classification of casualty statistics

Casualty statistics for World War I vary to a great extent; estimates of total deaths range from nine million to over 15 million. Military casualties reported in official sources list deaths due to all causes, including an estimated seven to eight million combat related deaths (killed or died of wounds) and another two to three million military deaths caused by accidents, disease and deaths while prisoners of war. Official government reports listing casualty statistics were published by the United States and Great Britain. These secondary sources published during the 1920s, are the source of the statistics in reference works listing casualties in World War I. This article summarizes the casualty statistics published in the official government reports of the United States and Great Britain as well as France, Italy, Belgium, Germany, Austria and Russia. More recently the research of the Commonwealth War Graves Commission (CWGC) has revised the military casualty statistics of the UK and its allies; they include in their listing of military war dead personnel outside of combat theaters and civilians recruited from Africa, the Middle East and China who provided logistical and service support in combat theaters. The casualties of these support personnel recruited outside of Europe were previously not included with British war dead, however the casualties of the Labour Corps recruited from the British Isles were included in the rolls of British war dead published in 1921. The methodology used by each nation to record and classify casualties was not uniform, a general caveat regarding casualty figures is that they cannot be considered comparable in all cases. First World War civilian deaths are "hazardous to estimate" according to Micheal Clodfelter who maintains that "the generally accepted figure of noncombatant deaths is 6.5 million."

Casualties by borders of 1914

{| class="wikitable sortable" style="text-align: right;"

|- valign=top

! Nation

! scope="col" data-sort-type="number"| Population (millions)

! scope="col" data-sort-type="number"| Combat deaths and missing in action (included in total military deaths)

! scope="col" data-sort-type="number"| Total military deaths (from all causes)

! scope="col" data-sort-type="number"| Civilian deaths (military action and crimes against humanity)

! scope="col" data-sort-type="number"| Increase in civilian deaths (malnutrition and disease excluding Influenza pandemic)

! scope="col" data-sort-type="number"| Total deaths

! scope="col" data-sort-type="number"| Deaths as % of population

! scope="col" data-sort-type="number"| Military wounded

! colspan=9 style="text-align:center;background:#B0C4DE" | Allies and co-belligerents of World War I

| align=left |

| 5.0

| 61,527

| 59,330 to 62,149

| align=left |

| 7.2

| 56,638

| 56,639

| 58,639 to 66,996

| % to %

| 149,732

| 16,711(included with UK)

| 1,204 to 1,570

| % to %

| 2,314

| 107,000 to 400,000

| 867,829 to 1,011,687

| % to %

| 1,675,000

| align=left | '

| 380.0

| 953,104

| 949,454 to 1,118,264

| 18,829

| 107,000

| 1,077,283 to 1,244,093

| % to %

2,101,077

| align=left |

| 7.4

| 38,170 to 58,637

| 23,700

| 62,000

| 123,870 to 144,337

| % to %

| 44,686

| 1,357,000

| 40,000

| 300,000

| align=left |

| 4.8

| 5,000

| 150,000

| 155,000 to 176,000

| % to %

| 21,000

| 3,400

| 332,000

| 1,052,400 to 1,301,400

| % to %

| 947,000

| 300 to 4,661

| % to %

| 907

| 82,000

| 89,235

| %

| 13,751

| 200,000

| 410,000

| 730,000 to 450,000

| 450,000

| 116,708

| 757

| 117,466

| %

| 204,002

| 1,200,000 to 1,494,200

| 467,000

| 1,787,000 to 2,081,200

| % to %

| 3,620,000

| 187,500

| %

| 152,390

| 2,037,000

| 300,000

| 2,198,420 to 2,800,720

| % to %

| 4,215,662

| 325,000

| 1,500,000

| 1,000,000

| 2,825,000 to 3,271,844

| % to %

| 400,000

| 700

| %

| —

| align=left |

| 0.3

| 2,800

| See footnote

|

| align=left |

| 2.4

| 1,180

| 2,000,000

| %

| —

| align=left |

| 5.6

| 800

|70,000

|8.75% to 10%

|—

| align=left |

|0.0087

|0.05%

|—

|- style="background:#ccc;"

| align=left | Grand total

| 959.7

| 8,042,189

| 8,573,058 to 10,824,240

| 2,250,099

| 5,411,000 to 8,100,000

| 15,000,000 to 22,000,000

Casualties by post-war (1924) borders

thumb|Europe 1914 and 1924

The war involved multi-ethnic empires such as Great Britain, France, Germany, Russia, Austria-Hungary and Turkey. Many ethnic groups in these territories were conscripted for military service. The casualties listed by modern borders are also included in the above table of figures for the countries that existed in 1914. The casualty figures by 1924 post war borders are rough estimates by Russian historian Vadim Erlikman in a 2004 handbook of human losses in the 20th century, the sources of his figures were published in the Soviet era and in post-Soviet Russia.

According to the 1914–1918 Online Encyclopedia "In addition to losses suffered by African military personnel and the laborers supporting their operations, very large, but unknown numbers of African civilians perished during the war." They made an estimate of civilian losses in Africa of 750,000 based on the study by the Vadim Erlikman. They noted that Erlikman's figures are based on the work of the Russian demographer Boris Urlanis, noting that these estimates were "imprecise" and "could be used to provide a frame of reference for further inquiry". The Oxford History of World War One notes that "In east and central Africa the harshness of the war resulted in acute shortages of food with famine in some areas, a weakening of populations, and epidemic diseases which killed hundreds of thousands of people and also cattle."

The following estimates of Austrian deaths, within contemporary borders, were made by a Russian historian in a 2004 handbook of human losses in the 20th century. Total dead 175,000: including military losses 120,000 with the Austro-Hungarian forces and POW deaths in captivity of 30,000. Civilian dead due to famine and disease were 25,000.

The following estimates of Belarusian deaths, within contemporary borders, were made by a Russian historian in a 2004 handbook of human losses in the 20th century. Total dead 130,000: including military losses 70,000 with the Russian forces. Civilian dead were 60,000.

The following estimates of Ukrainian deaths, within contemporary borders, were made by a Russian historian in a 2004 handbook of human losses in the 20th century. Total dead 590,000: including military losses 450,000,(Erlikman did not break out military losses between Austro-Hungarian and Russian armed forces). Civilian dead were 140,000.

The Belgian Congo was part of the Kingdom of Belgium during the war. A Russian historian Vadim Erlikman in a 2004 handbook of human losses in the 20th century based on sources published in the Soviet Union and Russia estimated a total of 155,000 deaths in the Belgian Congo during the war. The Czechoslovak Legions fought with the armies of the Allies during the war.

thumb|Austrian memorial commemorating soldiers from the village of [[Obermillstatt who died in World War I]]

Estonia was part of the Russian Empire during the war and about 100,000 Estonians served in the Russian Army. Of them about 10,000 were killed.

From 1809 Finland was an autonomous Grand Duchy in the Russian Empire until the end of 1917. Finland's autonomous status meant that Finns were exempt from conscription into the Russian Army. Approximately 800 Finns voluntarily served during World War I. According to data regarding Finnish war casualties, 317 Finns were killed between 1914 and 1917.

French colonies

The following estimates of deaths, within contemporary borders, during World War I were made by a Russian historian Vadim Erlikman in a 2004 handbook of human losses in the 20th century. Erlikman's estimates are based on sources published in the Soviet Union and Russia. These numbers only include military deaths, total civilian deaths in Africa could amount up to 750,000.

: (1914 known as French Algeria): 26,000

: (1914 known as French Indochina): 12,000

: (1914 part of French West Africa): 10,000

: (1914 known as the French protectorate of Morocco): 8,000

: (1914 part of French West Africa): 6,000

: (1914 part of French West Africa): 2,500

:: 2,500 military

: (1914 part of French West Africa): 2,000

: (1914 part of French Equatorial Africa): 2,000

: (1914 part of French West Africa): 2,000

: (1914 known as French Tunisia): 2,000

: (1914 part of French Equatorial Africa): 1,500

: (1914 known as French Oubangui-Chari): 1,000

: (1914 part of French West Africa): 1,000

: (1914 part of French Equatorial Africa): 500

: (French Establishments in India): 195

Total: 82,000

The following estimates of Georgian deaths, within contemporary borders, were made by a Russian historian in a 2004 handbook of human losses in the 20th century. Georgia was part of the Russian Empire during the war and about 150,000 Georgians served in the Russian Army. Of them about 10,000 were killed. These numbers only include military deaths, total civilian deaths in Africa could amount up to 750,000.

Ireland was a part of the United Kingdom during World War I. Five-sixths of the island left to form the Irish Free State, now the Republic of Ireland, in 1922. A total of 206,000 Irishmen served in the British forces during the war. The number of Irish deaths in the British Army recorded by the registrar general was 27,405. A significant number of these casualties were from what, in 1920, became Northern Ireland. While 49,400 soldiers died serving in Irish divisions (the 10th, 16th and 36th), although not all of the men serving in these divisions were natives of Ireland and many Irish who died in non-Irish regiments are not listed. For example, 29% of the casualties in the 16th Division were not natives of Ireland.

The losses of Portuguese Mozambique were estimated by a Russian historian Vadim Erlikman in a 2004 handbook of human losses in the 20th century. Erlikman's estimates are based on sources published in the Soviet Union and Russia. According to Micheal Clodfelter, Polish war dead were 1,080,000, whilst 200,000 Polish civilians were killed in the fighting on the Eastern Front; 870,000 men served in the German, Austrian and Russian armies. The ethnic Polish Blue Army served with the French Army. The ethnic Polish Legions fought as part of the Austro-Hungarian Army on the Eastern Front.

The territory of Transylvania was part of Austria-Hungary during World War I. The following estimates of Romanian deaths, within contemporary borders, during World War I were made by a Russian historian in a 2004 handbook of human losses in the 20th century. Total dead: 748,000, including military losses of 220,000 with the Romanian forces, 150,000 with the Austro-Hungarian forces and POW deaths in captivity of 48,000. Civilian dead were as follows due to famine and disease: 200,000, killed in military operations 120,000 and 10,000 dead in Austrian prisons.

Included with British casualties in East Africa are the deaths of 44,911 recruited labourers. The CWGC reports that nearly 2,000 workers from the Chinese Labour Corps are buried with British war dead in France.

The following estimates of British Empire colonial military deaths, within contemporary borders, during World War I were made by a Russian historian Vadim Erlikman in a 2004 handbook of human losses in the 20th century. Erlikman's estimates are based on sources published in the Soviet Union and Russia.

: (1914 known as the Gold Coast): 1,200

: (1914 known as British East Africa): 2,000

: (1914 known as Nyasaland): 3,000

: (1914 part of British West Africa): 5,000

: (1914 part of British West Africa): 1,000

: (1914 known as the Uganda Protectorate): 1,500

: (1914 known as Northern Rhodesia): 3,000

: (1914 known as Southern Rhodesia): 5,716 persons of European origin served in the war, of whom about 700 were killed, or died of wounds or other causes. In explicitly Rhodesian units, 127 were killed, 24 died of wounds, 101 died of disease or other causes and 294 were wounded. Of the territory's black African servicemen, 31 were killed in action, 142 died of other causes and 116 were wounded.

Total: 18,000

The following estimates are for Yugoslavia within the 1991 borders.

Slovenia, Croatia, Bosnia and Vojvodina (Now part of Serbia) were part of Austria-Hungary during World War I. Serbia, which included Macedonia, and Montenegro was an independent nation. The Yugoslav historian Vladimir Dedijer put the total losses of the Yugoslav lands at 1.9 million, of which 43% were from Serbia. The following estimates of Yugoslav deaths, within 1991 borders, during World War I were made by a Russian historian in a 2004 handbook of human losses in the 20th century. Total dead: 996,000 including military losses, 260,000 with the Serbian forces, 80,000 with the Austro-Hungarian forces, 13,000 with Montenegrin forces and POW deaths in captivity of 93,000. Civilian dead were as follows due to famine and disease: 400,000, killed in military operations: 120,000 and 30,000 dead in Austrian prisons or executed.

During World War I, the Nepalese army was expanded and six new regiments, totaling more than 20,000 troops—all volunteers—were sent to India, most of them to the North-West Frontier Province, to release British and Indian troops for service overseas. Simultaneously, the Nepalese government agreed to maintain recruitment at a level that would sustain the existing British Gurkha units and allow the establishment of additional ones. The battalions were increased to thirty-three with the addition of 55,000 new recruits and Gurkha units were placed at the disposal of the British high command for service on all fronts. Many volunteers were assigned to non-combat units, such as the Army Bearer Corps and the labour battalions but they also were in combat in France, Turkey, Palestine and Mesopotamia. The Rana prime ministers urged Nepalese males to fight in the war. Of the more than 200,000 Nepalese who served in the British army, there were some 20,000 Gurkha casualties included above with the British Indian Army.

Footnotes

thumb|Deaths by alliance and military/civilian. Most of the civilian deaths were due to war-related [[famine.]]

thumb|Deaths of the Allied powers

thumb|Deaths of the Central powers

East and Central Africa

The conflict in East Africa caused enormous civilian casualties. The Oxford History of World War One notes that "In east and central Africa the harshness of the war resulted in acute shortages of food with famine in some areas, a weakening of populations, and epidemic diseases which killed hundreds of thousands of people and also cattle."
The military casualties of the UK, France, Germany, Belgium and Portugal include Africans who served with their armed forces, the details are noted above in the list of the various colonies.

thumb|Fallen British and Australian soldiers in a mass grave, dug by German soldiers, 1916 or 1917

Australia

The Australian War Memorial puts their war dead at 61,513.
The Commonwealth War Graves Commission figure for Australian war dead is 62,149.

Belgium

Belgian government figures for military losses in Europe were 40,367 (26,338 killed, died of wounds or accidents and 14,029 died of disease or missing). In Africa: 2,620 soldiers were killed and 15,650 porters died. The combined total for Europe and Africa is 58,637.

Canada

According to the Canadian War Museum Close to 61,000 Canadians were killed during the war, and another 172,000 were wounded. The small Dominion of Newfoundland suffered 1,305 killed and several thousand wounded. The Canadian Expeditionary Force lost 59,544 in the war, including 51,748 due to enemy action; the Royal Canadian Navy reported 150 deaths from all causes and 1,388 Canadians died while serving with the British Flying Services.
The Commonwealth War Graves Commission figure for Canadian war dead is 64,996.
The 2,000 civilian deaths were due to the Halifax Explosion.
A breakdown of French casualties published in the Official History of the Australian Army Medical Services, 1914–1918 lists 674,700 killed in action, 250,000 died of wounds, 225,300 missing and presumed dead and 175,000 dead from disease and injury. Wounded amounted to 2,300,000.
The Soviet demographer Boris Urlanis estimated that included in total French military deaths are 1,126,000 killed and died of wounds. Luxembourg was occupied by Germany during the war. According to the Mobile Reference travel Guide 3,700 Luxembourg citizens served in the French armed forces, 2,800 gave their lives in the war. They are commemorated at the Gëlle Fra in Luxembourg. The French Armenian Legion served as part of the French armed forces during the war. French colonies, such as Algeria and Vietnam, also sent troops to fight and serve on the battlefront. American military historian Douglas Porch reported of the French Foreign Legion, in which most non-French nationals served, that some estimates put Legion casualties during the war as high as 31,000 of the 44,150 men who served in the Legion, a 70 per cent casualty rate.
According to a demographic study, there were 500,000 indirect deaths in France (300,000 deaths due to wartime privations and 200,000 in the Spanish flu pandemic). Another estimate of the demographic loss of the civilian population in the France during the war, put total excess deaths at 264,000 to 284,000, not including an additional 100,000 to 120,000 Spanish flu deaths. Civilian dead include 1,509 merchant sailors and 3,357 killed in air attacks and long range artillery bombardments Kramer quotes Huber as estimating 600,000 excess deaths, though it's unclear what proportion are due to influenza.
According to a demographic study there were 150,000 indirect deaths in Greece due to wartime privations.
United States War Dept. figures for Italian casualties are: Total mobilized force 5,615,000; total casualties 2,197,000 (killed and died 650,000; wounded 947,000; prisoners and missing 600,000). Civilian deaths due to military action were 3,400 (including 2,293 by attacks on shipping, 965 during air raids and 142 by sea bombardment). Kramer cites Mario Isnenghi and Giorgio Rochat, La Grande Guerra, 1914–1918 (Florence: Scandicci, 2000), pp. 301–2. They give excess war-related civilian mortality for the period 1915–18 of 606,407, of which influenza accounts for 274,041.
United States War Dept. figures for Japanese casualties are: total mobilized force 800,000; total casualties 1,210 (including Killed and died 300; wounded 907; Prisoners and missing 3).
The Commonwealth War Graves Commission figure for New Zealand war dead is 18,060.

thumb|Re-educating wounded. Blind French soldiers learning to make baskets, World War I.

Romania

In 1924, the Romanian government in a reply to a questionnaire from the International Labour Office, an agency of the League of Nations, reported 1,000,000 men mobilized and 250,000 dead and missing in World War I.
A Russian historian in a 2004 handbook of human losses in the 20th century estimated 330,000 civilian dead (120,000 due to military activity, 10,000 as prisoners and 200,000 caused by famine and disease).

Russian Empire

According to the Soviet demographer Boris Urlanis the sources for Russian casualties are difficult to ascertain. Casualty figures, compiled from the field reports during the war, were published in 1925 by the Soviet Central Statistical office They put Russia's total losses at 775,400 dead and missing, 348,500 disabled and 3,343,900 POW. Those evacuated to the rear area were 1,425,000 sick and 2,844,500 wounded. Included in these figures are battle casualties of 7,036,087. (626,440 killed in action, 17,174 died of wounds, 228,838 missing, 3,409,433 held as prisoners of war and 2,754,202 wounded in action). Urlanis believes that the figures for those killed were considerably underestimated, because a large part of the reports were lost in retreats. Urlanis estimated the actual total military war dead at 1,811,000 (killed 1,200,000, died of wounds 240,000, gassed 11,000, died from disease 155,000, POW deaths 190,000, deaths due to accidents and other causes 15,000).
A Russian historian in a 2004 handbook of human losses in the 20th century estimated 1,140,000 war related Russian civilian deaths, from 1914 to 1917 in 1914 borders (410,000 due to military operations and 730,000 caused by famine and disease).

Serbia

Sources for total Serbian casualties range from 750,000 to 1,250,000.
A demographic study in 1927, put total the war dead for Serbia and Montenegro at 750,000 (300,000 military and 450,000 civilians). The overall population loss from 1912 to 1920, based on the pre-war level was 1,236,000 persons (including 750,000 in World War I; 150,000 killed in the Balkan Wars and a decline in the number of births of 336,000), in addition there were 47,000 war related deaths during 1914–1920, that are included with deaths by natural causes. At a September 2014 conference sponsored by the Serbian Ministry of Defense, Dr. Alexander Nedok put Serbian war dead at 1,247,435 persons.
According to the Soviet demographer Boris Urlanis regarding Serbia "it is particularly difficult to ascertain the number of killed". Based on a demographic analysis of the population, Urlanis estimated total Serbian and Montenegrin casualties of 728,000 including military dead: 278,000 (140,000 killed in action; 25,000 died of wounds; 50,000 disease; 60,000 POW and 3,000 from other causes) and total civilian dead of 450,000.
In 1924, the Serbian government in a reply to a questionnaire from the International Labour Office, an agency of the League of Nations, reported 1,008,240 men mobilized and 365,164 dead and missing in World War I.
The report of the UK War Office listed 7,121 Army war dead, 12,029 wounded and 1,538 taken prisoner. Losses at sea were 908 UK civilians and 63 fisherman killed in U-boat attacks. According to the Commonwealth war Graves Commission "In all, nearly 2,000 men from the Chinese Labour Corps died during the First World War, some as a direct result of enemy action, or of wounds received in the course of their duties, but many more in the influenza epidemic that swept Europe in 1918–19" According to the Commonwealth War Graves Commission, "The African combatant troops raised for the East African campaign numbered 34,000. The non-combatant porters, stevedores and followers of the Military Labour Corps 600,000. Almost 50,000 of these men were lost, killed in action died of sickness or wounds"
Kramer gives 600,000 excess civilian deaths, of which 200,000 are due to the influenza pandemic, citing Brill’s Encyclopedia of the First World War, pp. 732–3. The U.S. casualty figures were revised by the US Dept. of Defense in 1957.
United States War Dept. figures from 1924 for U.S. casualties were: total mobilized force 4,355,000; total casualties 350,300 (including killed and died from all causes 126,000; wounded 234,300 (including 14,500 died of wounds); prisoners and missing 4,500).
In 1924, the U.S. government in a reply to a questionnaire from the International Labour Office, an agency of the League of Nations, reported 4,272,521 men mobilized and 67,813 dead and missing in World War I.
In 1924, the Austrian government in a reply to a questionnaire from the International Labour Office, an agency of the League of Nations, reported 9,000,000 men mobilized and 1,542,817 dead and missing in World War I.
The Soviet demographer Boris Urlanis estimated that included in total Austro-Hungarian military deaths are 900,000 killed and died of wounds.

Bulgaria

United States War Dept. figures for Bulgarian casualties are: total mobilized force 1,200,000; total casualties 266,919 (including Killed and died 87,500; wounded 152,930; Prisoners and missing 27,029).
The figures for civilian deaths due to the Blockade of Germany are disputed. The German Board of Public Health in December 1918 maintained that 763,000 German civilians died from malnutrition and disease caused by the blockade up until the end of December 1918. A German academic study in 1928 put the death toll at 424,000. A study sponsored by the Carnegie Endowment for International Peace in 1940, estimated the German civilian death toll due to the war at over 600,000. Based on the above-mentioned German study of 1928, they maintained that "A thorough inquiry has led to the conclusion that the number of "civilian" deaths traceable to the war was 424,000, to which number must be added about 200,000 deaths caused by the influenza epidemic". Finally, Kramer cites Jay Winter, who estimates 478,500 civilian war-related excess deaths, of which 180,000 was due to the influenze pandemic.]]

Ottoman Empire

Based on his analysis of the non-published individual World War I campaign histories in the Ottoman Archives, Edward J. Erickson estimated Ottoman military casualties in the study Ordered to Die: A History of the Ottoman Army in the First World War. The casualties included total war dead of 771,844, (243,598 killed in action, 61,487 missing action and 466,759 deaths due to disease). The number of wounded was 763,753 and POWs 145,104.
The Ottoman official casualty statistics published in 1922 were: total dead 325,000 including (killed in action 50,000, 35,000 died of wounds, 240,000 died of disease). Wounded 400,000. POWs, sick and missing 1,565,000 and total mobilized: 2,850,000.
United States War Dept. figures for Ottoman casualties are: total mobilized force 2,850,000; total casualties 975,000 (including killed and died 325,000; wounded 400,000; prisoners and missing 250,000).
The Soviet demographer Boris Urlanis estimated that included in total Ottoman military deaths are 318,000 killed and died of wounds. A Russian historian in a 2004 handbook of human losses in the 20th century estimated total Ottoman civilian dead from 1915 to 1918 at about 3.2 million including the deaths of 2.2 million Armenian, Assyrian, and Greek victims of genocides committed by the Ottomans and 1,000,000 war-related civilian deaths in the Ottoman Empire due to famine and disease.(In current borders Turkey 500,000; Syria 160,000; Lebanon 110,000; Iraq 150,000; Israel/Palestine 35,000 and Jordan 20,000) According to the BBC 200,000 persons perished in the Great Famine of Mount Lebanon during the war.
Civilian casualties include the Armenian genocide. The total number of resulting Armenian deaths is generally held to have been 1.5 million. The overwhelming majority of historians as well as academic institutions on Holocaust and Genocide Studies recognize the Armenian Genocide. "Despite the vast amount of evidence that points to the historical reality of the Armenian Genocide, eyewitness accounts, official archives, photographic evidence, the reports of diplomats, and the testimony of survivors, denial of the Armenian Genocide by successive regimes in Turkey has gone on from 1915 to the present".

Denmark

Denmark was neutral in the war but Germany at that time included part of Danish Schleswig. Men from this area were conscripted into the German forces and their losses are included with German casualties. Over 700 Danish merchant sailors and fisherman died, mostly due to vessels torpedoed by German submarines.

Luxembourg

Luxembourg remained under German occupation during the war. The government, led by Paul Eyschen, chose to remain neutral. This strategy had the approval of Marie-Adélaïde, Grand Duchess of Luxembourg. Some citizens were conscripted into the German forces and others escaped to volunteer for the Allies. According to the Mobile Reference travel Guide, 3,700 Luxembourgeois citizens served in the French armed forces and 2,800 gave their lives in the war. They are commemorated at the Gëlle Fra in Luxembourg.

Liechtenstein

Liechtenstein was neutral in the war yet held sympathies to the Central Powers, particularly Austria-Hungary. As such, a number of Liechtensteiner citizens volunteered for both the German and Austro-Hungarian armies, of which 4 were confirmed to have been killed.
Sources for British Empire casualties are divergent and contradictory. The report of the War Office published in 1922 put the total number of British Empire "soldiers who lost their lives" at 908,371. On a separate schedule the War Office listed the losses of the Royal Navy at 32,237 dead and missing. It is implicit in this presentation that the figures for "soldiers who lost their lives" do not include the Royal Navy. However many published reference works list total British Empire(including the Dominions) losses at 908,371, it is implicit in these presentations that the figures for total losses include the Royal Navy. The War Office report did not explain the reason for this discrepancy; the difference is more than likely due to their inclusion of the Royal Naval Division and deaths outside of combat theaters.
Casualties and Medical Statistics published in 1931. was the final volume of the Official Medical History of the War, gives British Empire, including the Dominions, for Army losses by cause of death. Total war dead in combat theaters from 1914 to 1918 were 876,084, which included 418,361 killed, 167,172 died of wounds, 113,173 died of disease or injury, 161,046 missing and presumed dead and 16,332 prisoner of war deaths. Also listed were 2,004,976 wounded and 6,074,552 sick and injured. Total losses were not broken out for the UK and each Dominion, the figures are for losses in combat theaters only and do not include casualties of forces stationed in the UK from accidents or disease, casualties of the Royal Naval Division are also not included in these figures; the losses of the Gallipoli Campaign are for British forces only, since records for Dominion forces were incomplete. This study published by the Carnegie Endowment for International Peace, lists official French government figures for war-related military deaths and missing of France and its colonies.
Mortara, Giorgo La Salute pubblica in Italia durante e dopo la Guerra, New Haven: Yale University Press 1925. The official government Italian statistics on war dead are listed here. A brief summary of data from this report can be found online. go to Vol 13, No. 15
The demographer Boris Urlanis, analysis of the military dead for the belligerents in the war including his estimates for the combat related deaths included in total deaths.
Erickson, Edward J. Ordered to Die: A History of the Ottoman Army in the First World War The authors estimates were made based data from official Ottoman sources.
Hersch, Liebmann, La mortalité causée par la guerre mondiale, Metron. The International Review of Statistics, 1927, Vol 7. No 1. This study published in an academic journal, detailed the demographic impact of the war on France, the UK, Italy, Belgium, Portugal, Serbia, Romania and Greece. The total estimated increase in the number of civilian deaths due to the war was 2,171,000, not including an additional 984,000 Spanish flu deaths. These losses were due primarily wartime privations.
Dumas, Samuel (1923). Losses of Life Caused by War published by Oxford University Press. This study detailed the impact of the war on the civilian population. The study estimated excess civilian deaths at: France (264,000 to 284,000), the UK (181,000), Italy (324,000) and Germany(692,000).
In The International Labour Office, an agency of the League of Nations, published statistics on the military dead and missing for the belligerents in the war.

The source of population data is:

Haythornthwaite, Philip J., The World War One Source Book pp. 382–383