Formerly known as the eastern pipistrelle, based on the errant belief that it was closely related to European Pipistrellus species, the closest known relative of the tricolored bat is now recognized as the canyon bat. Its common name "tricolored bat" derives from the coloration of the hairs on its back, which have three distinct color bands. It is the smallest bat species in the eastern and midwestern US, with individuals weighing only 4.6–7.9 g (0.16–0.28 oz).