Kakutani equivalence is a notion of equivalence which is stronger than orbit equivalence but weaker than measurable conjugacy. Ratner developed an entropy-like invariant of Kakutani equivalence to exhibit two homogeneous flows which were not Kakutani equivalent. We compute this invariant for every unipotent flow on compact homogeneous spaces of semisimple groups. The answer is strikingly different from the case of nilflows. We also compute the slow entropy, introduced by Katok and Thouvenot, for such flows. Joint with Adam Kanigowski and Daren Wei.