The human capital of black soldiers during the American Civil War

•Age heaping is used to measure the human capital of black soldiers.•Black soldiers during the Civil War were found to be endowed with high human capital.•The human capital of black soldiers was only slightly lower than that of white soldiers.•This attribute could partially explain the great achievements of black soldiers.

Analyzing three datasets on black and white soldiers and the black and white populations from the same birth years, this paper finds that black soldiers during the American Civil War had much higher human capital than the black population.