How many African American served in the confederate army?

Absolute precision with numbers in the Civil War is impossible for either side. Numbers given are the best estimates resulting from careful scholarship. That said the best guess is that around 180,000 blacks served in the Union Army, out of a probable total of 2.1 million, so they were something less than 9% of the total army. 1800 black soldiers are recorded as having died in the service, or about .5% of all Union dead, which were in the 360,000 range. This figure of dead black soldiers is probably low. The precise number who served can never be given with certainty because the Union army counted enlistments, and some men enlisted more than once.