The toco toucan has a striking plumage with a mainly black body, a white throat, chest and uppertail-coverts, and red undertail-coverts. What appears to be a blue iris is actually thin blue skin around the eye. This blue skin is surrounded by another ring of bare, orange skin. The most noticeable feature, however, is its huge bill, which measures from in length, which is yellow-orange, tending to deeper reddish-orange on its lower sections and culmen, and with a black base and large spot on the tip. It looks heavy, but as in other toucans it is relatively light because the inside largely is hollow. The tongue is nearly as long as the bill and very flat. This species is the largest toucan and the largest representative of the order Piciformes. The total length of the species is . Body weight in these birds can vary from , with males averaging against the smaller female, which averages . Among standard measurements, the wing chord is , the tail is and the tarsus is . Other than the size difference, there are no external differences between the sexes. Juveniles are duller and shorter-billed than adults. Its voice consists of a deep, coarse croaking, often repeated every few seconds. It also has a rattling call and will bill-clack.