No one, not even the United States government, knows how many civilians it has killed during the so-called war on terror. Since absolute numbers are elusive, I’ve provided as clear a picture as I can provide. The resources linked to in this post contain a wealth of information on the number of civilians killed by American strikes.
As of this writing, the Bureau of Investigative Journalism estimates that US covert strikes in Afghanistan, Pakistan, Somalia, and Yemen have killed between 739 and 1407 civilians. Between 240 and 307 of the killed civilians were children.
On July 1, 2016, the Obama administration announced that air strikes from the beginning of Obama’s presidency through the end of 2015 killed between 64 and 116 civilians. The numbers provided by the administration didn’t include civilians killed in Afghanistan, Syria, or Iraq because they are deemed “areas of active hostilities.”
That same day, the Bureau of Investigative Journalism put the number of civilians killed in Afghanistan, Pakistan, Somalia, and Yemen from the start of the Obama presidency through the end of 2015 as between 380 and 801. Interestingly, the number of total dead reported by the administration was 2,436. The number of total killed estimated by the Bureau of Investigative Journalism was 2,753.
On May 29, 2012, The New York Times reported that the Obama administration counted any male of fighting age as an enemy combatant, unless clear proof to the contrary was shown.
Recently, the Trump administration acknowledged that a March strike in Mosul, Iraq killed 105 civilians.
Here’s an article from The Atlantic that discusses Obama’s drone program.
This article from Foreign Policy.com provides more information about the inaccurate numbers released by the Obama Administration.