In mathematics, two metrics on the same underlying set are said to be equivalent if the resulting metric spaces share certain properties. Equivalence is a weaker notion than isometry; equivalent metrics do not have to be literally the same. Instead, it is one of several ways of generalizing equivalence of norms to general metric spaces.

Throughout the article, ${\displaystyle X}$ will denote a non-empty set and ${\displaystyle d_{1}}$ and ${\displaystyle d_{2}}$ will denote two metrics on ${\displaystyle X}$.