Rafinesque's big-eared bat is around 7.5–10 cm (3.0–3.9 in) long. It has a wingspan of 25–30 cm (10–12 in). They weigh from 6–13 g (0.21–0.46 oz). The bat is gray on the dorsal side and white on the underside. The ears and face are a pinkish-brown color, while the arm and wing are dark brown.