Gromov's universal filling inequalities relate the filling radius and the
filling volume of a Riemannian manifold to its volume. The main result of the
present article is that in dimensions at least three the optimal constants in
the filling inequalities depend only on dimension and orientability, not on the
manifold itself. This contrasts with the analogous situation for the optimal
systolic inequality, which does depend on the manifold.Comment: 13 pages. Corrected some minor errors. To appear in Journal f\"ur die
reine und angewandte Mathematik (Crelle's Journal