The purple heron is a large bird, 78–97 cm (31–38 in) in length with a standing height from 70 to 94 cm (28 to 37 in) and a 120–152 cm (47–60 in) wingspan. However, it is slender for its size, weighing only 0.5–1.35 kg (1.1–3.0 lb). It is somewhat smaller than the grey heron, from which it can be distinguished by its darker reddish-brown plumage, and, in adults, darker grey back. It has a narrower yellow bill, which is brighter in breeding adults. The most similarly-coloured heron is the Goliath heron, which is considerably larger.