Answer:
Well, you can not tell the exact numbers of the Non-Jewish civilian who were killed during Holocaust bu according to historians and sources Approximately "4000 non-Jewish civilians" were also killed in the Holocaust.
The holocaust was the state-sponsored murder of Germany's Jews, Nazis called it a perfect solution when Hitler's Nazi party came into power in Germany they believed that Germans were racially superior and the Jews are inferior community who are polluting their so-called racial superior community so they start killing Jews people on mass numbers but there were other communities were also there such as "ROMANI GYPSIES".