Ranking · wars and genocides · central estimates
The deadliest wars in history
From the Mongol conquests to the wars of this decade, ranked by death toll — with the range behind each figure, how long each war lasted, and how fast it killed.
Short answer
The deadliest war in history is World War 2 (1939–1945), with 70 to 85 million dead — about 3 % of the world's population, and for the first time in a major war far more civilians than soldiers. It is followed by the Mongol conquests of the 13th century (estimates up to 40 million) and the Taiping Rebellion in China (20–30 million). This list ranks 21 wars and genocides documented in the DeathVault archive.
Full ranking
| # | War | Period | Years | Deaths (central) | Range | Deaths / year | % of world pop. |
|---|---|---|---|---|---|---|---|
| 1 | World War II | 1939–1945 | 6 | 75.0M | 70.0M – 85.0M | 12.5M | 3.3% |
| 2 | Mongol Conquests | 1206–1368 | 162 | 40.0M | 30.0M – 50.0M | 247K | 10.0% |
| 3 | Taiping Rebellion | 1850–1864 | 14 | 30.0M | 20.0M – 40.0M | 2.1M | 2.5% |
| 4 | World War I | 1914–1918 | 4 | 20.0M | 17.0M – 22.0M | 5.0M | 1.1% |
| 5 | Second Sino-Japanese War | 1937–1945 | 8 | 14.0M | 8.0M – 22.0M | 1.8M | — |
| 6 | The Holocaustgenocide | 1941–1945 | 4 | 11.0M | 9.0M – 11.0M | 2.8M | — |
| 7 | Thirty Years' War | 1618–1648 | 30 | 8.0M | 5.0M – 12.0M | 267K | — |
| 8 | Russian Civil War | 1917–1922 | 5 | 7.0M | 5.0M – 9.0M | 1.4M | — |
| 9 | Napoleonic Wars | 1803–1815 | 12 | 5.0M | 3.5M – 6.0M | 417K | — |
| 10 | Chinese Civil War | 1927–1949 | 22 | 5.0M | 2.0M – 8.0M | 227K | — |
| 11 | Second Congo War | 1998–2003 | 5 | 3.8M | 2.7M – 5.4M | 760K | — |
| 12 | Korean War | 1950–1953 | 3 | 2.5M | 1.2M – 4.5M | 833K | — |
| 13 | Vietnam War | 1955–1975 | 20 | 2.0M | 1.3M – 3.5M | 100K | — |
| 14 | Nigerian Civil War (Biafra) | 1967–1970 | 3 | 2.0M | 1.0M – 3.0M | 667K | — |
| 15 | Atlantic Slave Tradegenocide | 1500–1900 | 400 | 2.0M | 1.8M – 4.0M | 5K | — |
| 16 | Cambodian Genocidegenocide | 1975–1979 | 4 | 1.7M | 1.5M – 2.0M | 425K | — |
| 17 | Rwandan Genocide | 1994 | 1 | 800K | 500K – 800K | 800K | — |
| 18 | War of the Triple Alliance | 1864–1870 | 6 | 800K | 400K – 1.2M | 133K | — |
| 19 | Syrian Civil War | 2011–2024 | 13 | 500K | 300K – 600K | 38K | — |
| 20 | Russia–Ukraine War | 2022–present | 4 | 300K | 150K – 500K | 75K | — |
| 21 | Israel–Gaza Wargenocide | 2023–present | 3 | 65K | 50K – 250K | 22K | — |
Central estimate and low–high range per our methodology; war-attributable famine and disease are included where a credible demographic study exists. Deaths per year is the central figure divided by the war's duration (minimum one year) — a rough measure of intensity, not of suffering.
Why the twentieth century dominates
Seven of the ten deadliest wars began after 1850. This is partly population — there were four times as many people alive in 1939 as in 1650 — and partly capability: railways, conscription, industrial production and, later, air power let states mobilise entire populations and target entire cities. The Thirty Years' War killed perhaps 8 million people over three decades, mostly by famine and plague among a population of a few tens of millions; World War 2 killed ten times as many in six years.
Soldiers versus civilians
In the wars of the eighteenth and nineteenth centuries most of the dead were soldiers, and most of those died of disease rather than wounds. The twentieth century inverted the ratio. World War 1 killed roughly 9–11 million soldiers and 6–13 million civilians; World War 2 killed 21–25 million soldiers and 50–55 million civilians — through genocide, deliberate starvation, forced labour and the bombing of cities. Every war since has followed the modern pattern: in the Second Congo War, the Syrian civil war and the war in Ukraine the great majority of the dead are civilians, and most of them die of the war's consequences rather than its weapons.
The wars that are hardest to count
The Mongol conquests, the Taiping Rebellion and the Chinese civil wars carry the widest ranges on this page because the sources are fragmentary and the deaths are demographic — whole regions depopulated by famine, flight and disease over decades. Chinese census figures fell by tens of millions across the Taiping period; how much of that was death rather than displacement or uncounted survivors is exactly what historians argue about. We show the range and choose a central figure inside the mainstream, never the most dramatic estimate.
Genocides on this list
The Holocaust, the Rwandan genocide, the Cambodian genocide and the Atlantic slave trade are included here as mass-killing events rather than wars in the conventional sense. The Holocaust's 6 million (about 11 million counting all victims of Nazi mass killing) is already part of World War 2's civilian toll; both appear because both are searched for and documented separately.
Frequently asked questions
What is the deadliest war in history?
World War 2 (1939–1945): 70–85 million deaths, including 50–55 million civilians. The Soviet Union lost the most people (24–27 million), followed by China (15–20 million); Poland lost the largest share of its population, around 17 %.
What was the deadliest war before the twentieth century?
The Mongol conquests of the 13th century, with estimates of 20–40 million dead across China, Central Asia, Persia and Eastern Europe — perhaps 10 % of the world's population at the time. The Taiping Rebellion (1850–1864) killed 20–30 million in China alone.
How many people died in World War 1?
About 15–22 million: 9–11 million military deaths and 6–13 million civilians, most of the latter from war-related famine and disease (including deaths in the Ottoman Empire and the Russian famine that followed). The 1918 influenza pandemic, which overlapped the war's final year, is counted separately.
What is the deadliest war of the 21st century?
By documented death toll, the Second Congo War (1998–2003), with estimates of 2.5–5.4 million deaths, most from disease and starvation. The Syrian civil war (over 500,000) and the war in Ukraine are the largest conflicts of the last fifteen years.
Do these numbers include deaths from famine and disease caused by the war?
Yes, when a credible demographic study attributes them to the war — which is the case for the Thirty Years' War, the Taiping Rebellion, World War 1, World War 2 and the Second Congo War. Each event page states which measure its central figure uses. See the Methodology page for the full rule.