The Common Spotted Flat has a wingspan or around 30–35 mm. A dull black or brown butterfly with semi transparent spot on the wings and sometimes with no visible spots. The underside of the wings is grey-brown with diffused dark spots. The male and female are similar in shape and colour and with hardly any differentiation. Both sexes of the flat are similar in appearance, being dull brownish-black above and greyer in colour below. The butterflies have small, semi-transparent discal, cell and apical spots. The dark spots on the underside of the forewing are large, dark and diffused.