Since 9/11, it is estimated that just over 800,000 people have been killed in wars involving the United States around the world. The figure comes from Brown University's Costs of War Project which provides a conservative estimate of deaths in major warzones up until mid November 2019. The research takes into account deaths involving civilians, U.S. and allied troops, contractors, security forces, oppositon fighters, media workers and humanitarian workers across warzones in Afghanistan, Pakistan, Iraq, Syria and Yemen.

It found that Afghanistan experienced approximately 157,000 deaths since 9/11 while up to 308,000 people may have lost their lives in Iraq. The Syria war and efforts to defeat ISIS have resulted in an estimated 179,000 fatalities while war in Yemen and Pakistan has killed 90,000 and 66,000 people respectively. Out of the 800,000 total, the study estimates that 335,745 of those killed in global conflicts were civilians while just over 7,000 American servicemembers have also been killed.