Polycarbonate diol with a eleveda primary terminal OH ratio.

Disclosed is a polycarbonate diol having diol monomer units and carbonate monomer units, wherein the amount of at least one diol monomer unit selected from the group consisting of a 1,5-pentanediol unit and a 1,6-hexanediol unit is from 50 to 100 % by mole, based on the total molar amount of the diol monomer units, and wherein the ratio of primary hydroxyl groups in all terminal groups of the polycarbonate diol is in a specific range. Also disclosed is a thermoplastic polyurethane obtained by copolymerizing the above-mentioned polycarbonate diol and a polyisocyanate.