The constitution considered slaves as what percent of a free person?

Under the Three-Fifths Compromise, the Constitution considered slaves as 60% of a free person.

Explanation:

The Three-Fifth Compromise was a compromise established at the 1787 Philadelphia Convention between Northern and Southern colonies. This compromise considered, in the counting rules of persons represented in the House of Representatives, that a slave was counted for three-fifths of a free man. This compromise proposed by James Wilson and Roger Sherman was included in the United States Constitution, in Article 1, Section 2, Clause 3.

This was important because the population count would then be used to determine how many seats each state would have in the House of Representatives. The Compromise of the Three-Fifths gave a disproportionate representation of slave states in the House of Representatives compared to voters in free states until the Civil War. Section 2 of the Fourteenth Amendment, adopted in 1868, explicitly repealed the Three-Fifths Compromise.