Estimates for the total death count of the Second World War generally range somewhere between 70 and 85 million people. The Soviet Union suffered the highest number of fatalities of any single nation, with estimates mostly falling between 22 and 27 million deaths. China then suffered the second greatest, at around 20 million, although these figures are less certain and often overlap with the Chinese Civil War. Over 80 percent of all deaths were of those from Allied countries, and the majority of these were civilians. In contrast, 15 to 20 percent were among the Axis powers, and the majority of these were military deaths, as shown in the death ratios of Germany and Japan. Civilian deaths and atrocities It is believed that 60 to 67 percent of all deaths were civilian fatalities, largely resulting from war-related famine or disease, and war crimes or atrocities. Systematic genocide, extermination campaigns, and forced labor, particularly by the Germans, Japanese, and Soviets, led to the deaths of millions. In this regard, Nazi activities alone resulted in 17 million deaths, including six million Jews in what is now known as The Holocaust. Not only was the scale of the conflict larger than any that had come before, but the nature of and reasoning behind this loss make the Second World War stand out as one of the most devastating and cruelest conflicts in history. Problems with these statistics Although the war is considered by many to be the defining event of the 20th century, exact figures for death tolls have proven impossible to determine, for a variety of reasons. Countries such as the U.S. have fairly consistent estimates due to preserved military records and comparatively few civilian casualties, although figures still vary by source. For most of Europe, records are less accurate. Border fluctuations and the upheaval of the interwar period mean that pre-war records were already poor or non-existent for many regions. The rapid and chaotic nature of the war then meant that deaths could not be accurately recorded at the time, and mass displacement or forced relocation resulted in the deaths of many civilians outside of their homeland, which makes country-specific figures more difficult to find. Early estimates of the war’s fatalities were also taken at face value and formed the basis of many historical works; these were often very inaccurate, but the validity of the source means that the figures continue to be cited today, despite contrary evidence.

In comparison to Europe, estimate ranges are often greater across Asia, where populations were larger but pre-war data was in short supply. Many of the Asian countries with high death tolls were European colonies, and the actions of authorities in the metropoles, such as the diversion of resources from Asia to Europe, led to millions of deaths through famine and disease. Additionally, over one million African soldiers were drafted into Europe’s armies during the war, yet individual statistics are unavailable for most of these colonies or successor states (notably Algeria and Libya). Thousands of Asian and African military deaths went unrecorded or are included with European or Japanese figures, and there are no reliable figures for deaths of millions from countries across North Africa or East Asia. Additionally, many concentration camp records were destroyed, and such records in Africa and Asia were even sparser than in Europe. While the Second World War is one of the most studied academic topics of the past century, it is unlikely that we will ever have a clear number for the lives lost in the conflict.

Russian mortality rates during the Second World War were among the highest in the world. In terms of distribution, over one quarter of all deaths were of infants who had not yet reached one year old, and almost half of all deaths took place among children below the age of five. The distribution of these deaths varied between urban and rural regions, with a higher share of adults dying in urban areas.

The disproportionate impact of the war on male mortality rates, alongside the fact that the natural life expectancy among men is lower than that of women, meant that the share of men who died between the ages of 15 and 64 was much higher than female death rates. For women, the share of deaths among the youngest and oldest age groups were higher than those of men.

The 20th century marked a new trend in the recording of war fatalities, where more attention was given to the impact of conflicts on civilian populations, and not just the military. During the Second World War, the extent of the atrocities committed, the large-scale bombing campaigns, and the various famines resulting from the war meant that the scope of the civilian death toll took place was unprecedented - the likes of which had never been seen before, or since. Almost two thirds of all deaths due to the Second World War were of civilians, yet the ratio of military to civilian deaths varied greatly by country. Many British dominions and the United States suffered little to no civilian deaths as they were not located in an active theater of war - civilian fatalities largely came from naval or aerial attacks (such as at Pearl Harbor). In contrast, there were several European colonies in the Asia-Pacific region where all, or at least 95 percent, of total fatalities were among civilians - some of these regions suffered millions of deaths due to famine and atrocities.

It is estimated that the Second World War was responsible for the deaths of approximately 3.76 percent of the world's population between 1939 and 1945. In 2022, where the world's population reached eight billion, this would be equal to the death of around 300 million people.

The region that experienced the largest loss of life relative to its population was the South Seas Mandate - these were former-German territories given to the Empire of Japan through the Treaty of Versailles following WWI, and they make up much of the present-day countries of the Marshall Islands, Micronesia, the Northern Mariana Islands (U.S. territory), and Palau. Due to the location and strategic importance of these islands, they were used by the Japanese as launching pads for their attacks on Pearl Harbor and in the South Pacific, while they were also taken as part of the Allies' island-hopping strategy in their counteroffensive against Japan. This came at a heavy cost for the local populations, a large share of whom were Japanese settlers who had moved there in the 1920s and 1930s. Exact figures for both pre-war populations and wartime losses fluctuate by source, however civilian losses in these islands were extremely high as the Japanese defenses resorted to more extreme measures in the war's final phase.

In 1941, in the eastern, rural regions of Soviet Russia, almost 54 percent of all deaths were of children below the age of five years, and almost one third of all deaths (or roughly three fifths of deaths in the 0-4 age bracket) were of infants who were yet to reach their first birthday. This spike in child mortality was largely due to the redirection of manpower, as well as medical resources, to the frontlines, along with disruptions in food supplies, and the general destruction caused by the war. As conditions improved, the share of child deaths in subsequent years saw a significant reduction, however a large part of this was also due to the drop in fertility caused by the war, where fewer children died as there were simply fewer children born in these years.

The German invasion of the Soviet Union, in 1941, resulted in a dramatic rise in infant and child mortality rates. While the war was still ongoing in 1944, in Russia, the proportion of female deaths among children under five years was over 60 percent lower than it had been in the invasion's first year. In 1941, 51 percent of all female deaths were among those under five years old, and 29 percent of all female deaths were among infants below the age of one year. In comparison, the figures for male deaths were slightly lower among infants, as a higher share of the adult male population died as a direct result of the conflict, although the crude death rate (i.e. total number of deaths) was significantly higher in these years than at any other time in Soviet history.

The Empire of Japan's military losses in the Second World War are estimated to exceed 2.5 million men. For Japan, the costliest front in the Pacific theater was the battle against the United States in the Philippines, closely followed by its invasion of China, known as the Second Sino-Japanese War. After 1941, the Imperial Japanese Army was simultaneously stretched across several frontlines in the Pacific theater, and this was one contributing factor to their eventual defeat as reinforcing and supplying various armies across these fronts was unfeasible in the long-term.

The spike in infant and child mortality rates due to Operation Barbarossa, the German invasion of the Soviet Union, meant that almost half of all deaths in Soviet Russia in 1941 were among those below the age of five, and the majority of those were among infants below the age of one year. The consequences of this and the decrease in Soviet fertility can be observed in the unusually-low mortality rates among infants in 1942. Because of this spike, the share of deaths across other age groups was lower than what would have been typical of Russia in terms of its demographic development. The share of deaths among children then decreased as the war progressed and the conflict moved west, although it remained disproportionately high until the late 1940s.

The CenSoc WWII Army Enlistment Dataset is a cleaned and harmonized version of the National Archives and Records Administration’s Electronic Army Serial Number Merged File, ca. 1938 - 1946 (2002). It contains enlistment records for over 9 million men and women who served in the United States Army, including the Army Air Corps, Women's Army Auxiliary Corps, and Enlisted Reserve Corps. We publish links between men in the CenSoc WWII Army Enlistment Dataset, Social Security Administration mortality data, and the 1940 Census. The CenSoc Enlistment-Census-1940 file links these enlistment records to the complete 1940 Census, and may be merged with IPUMS-USA census data using the HISTID identifier variable. The CenSoc Enlistment-Numident file links enlistment records to the Berkley Unified Numident Mortality Database (BUNMD), and the CenSoc Enlistment-DMF file links enlistment records to the Social Security Death Master File. For enlistment records in the Enlistment-Numident and Enlistment-DMF datasets that have been independently and additionally linked to the 1940 Census, we include the HISTID identifier variable that can be used to merge the data with IPUMS census data.

During the World War II and Korean War era, the U.S. military freely distributed cigarettes to overseas personnel and provided low-cost tobacco products on domestic military bases. In fact, even today the military continues to sell subsidized tobacco products on its bases. Using a variety of instrumental variables approaches to deal with nonrandom selection into the military and into smoking, we provide substantial evidence that cohorts with higher military participation rates subsequently suffered more premature mortality. More importantly, we show that a large fraction, 35 to 79 percent, of the excess veteran deaths due to heart disease and lung cancer are attributable to military-induced smoking.

Operation Barbarossa, the German invasion of the Soviet Union, was one of the largest and most destructive invasions in history. The crude death rate of Soviet Russia increased significantly across all age groups in this time, although the distribution of deaths varied by age group. Infants and children made up the largest share of male deaths in unoccupied, urban regions, with 44 percent of all male deaths taking place among those aged below five years old. However, the disproportionate impact of the conflict on male death rates meant that the distribution of male deaths among young boys was lower than that of young girls, as the share of deaths in adult populations was generally higher among men.

Code and data to replicate the paper:"Increased mortality of white Americans and a decline in the health of cohorts born after World War II" Nicholas ReynoldsAccepted at the Journal of Human Resources.

Although the Japanese invasion of China, known as the Second Sino-Japanese War, lasted for more than eight years, it was the battle against the United States and local defenses for control of the Philippines that resulted in the largest share of Japan's military losses in the Second World War. The Japanese invasion of the Philippines began on December 8, 1941, on the same day as the attack on Pearl Harbor. The Japanese were able to take de facto control of the region by May 1942. Japan faced strong, underground resistance from locals in the two years that followed, until the U.S. military began its counteroffensive in the Leyte Gulf in October 1944, which continued until the war's end. Around 420,000 of the 490,000 Japanese deaths in the Philippines occurred during the Second Philippines Campaign (after Oct. 1944), although some estimates suggest that up to 80 percent of these deaths were due to starvation and malnutrition, as the Japanese supply lines became overstretched in the war's latter phase and failed to provide sufficient food and medicine to its forces.

Relationship between regional tuberculosis rates and Fisher Index.

The American Civil War is the conflict with the largest number of American military fatalities in history. In fact, the Civil War's death toll is comparable to all other major wars combined, the deadliest of which were the World Wars, which have a combined death toll of more than 520,000 American fatalities. The ongoing series of conflicts and interventions in the Middle East and North Africa, collectively referred to as the War on Terror in the west, has a combined death toll of more than 7,000 for the U.S. military since 2001. Other records In terms of the number of deaths per day, the American Civil War is still at the top, with an average of 425 deaths per day, while the First and Second World Wars have averages of roughly 100 and 200 fatalities per day respectively. Technically, the costliest battle in U.S. military history was the Battle of Elsenborn Ridge, which was a part of the Battle of the Bulge in the Second World War, and saw upwards of 5,000 deaths over 10 days. However, the Battle of Gettysburg had more military fatalities of American soldiers, with almost 3,200 Union deaths and over 3,900 Confederate deaths, giving a combined total of more than 7,000. The Battle of Antietam is viewed as the bloodiest day in American military history, with over 3,600 combined fatalities and almost 23,000 total casualties on September 17, 1862. Revised Civil War figures For more than a century, the total death toll of the American Civil War was generally accepted to be around 620,000, a number which was first proposed by Union historians William F. Fox and Thomas L. Livermore in 1888. This number was calculated by using enlistment figures, battle reports, and census data, however many prominent historians since then have thought the number should be higher. In 2011, historian J. David Hacker conducted further investigations and claimed that the number was closer to 750,000 (and possibly as high as 850,000). While many Civil War historians agree that this is possible, and even likely, obtaining consistently accurate figures has proven to be impossible until now; both sides were poor at keeping detailed records throughout the war, and much of the Confederacy's records were lost by the war's end. Many Confederate widows also did not register their husbands death with the authorities, as they would have then been ineligible for benefits.

Data on suicide cases committed prisoners classified as homosexuals in Sachsenhausen camp.