What percent of the world's population was killed in World War 1?

World War I resulted in an estimated 15 to 20 million deaths, including both military personnel and civilians. Given that the world's population at the time was approximately 1.8 billion, this means that roughly 0.8% to 1.1% of the global population was killed during the conflict. The war had a profound impact on many nations and societies, reshaping the political landscape of the world.