An interpolation estimate is a sufficient condition for the evaluation map to be surjective; it is dual to a multiplicity estimate, which deals with injectivity. Masser's first interpolation estimate on commutative algebraic groups can be generalized, and made essentially as precise as the best known multiplicity estimates in this setting. As an application, we prove a result that connects interpolation and multiplicity estimates. This is a joint work with M. Nakamaye.