This is a huge bird that regularly attains a height of 150 cm (59 in), a length of 142 cm (56 in) and a 2.4–2.7 m (7.9–8.9 ft) wingspan. The male is larger and heavier than the female, with a range of 5.1–7.5 kg (11–17 lb). The female is usually between 5 and 7 kg (11 and 15 lb). It is probably the tallest of the storks (though not the heaviest), due in no small part to it extremely long legs (tarsus length is up to 36.5 cm (14.4 in)). The long bill measures from 27.3 to 36 cm (10.7 to 14 in) The sexes can be readily distinguished by the golden yellow irises of the female and the brown irises and dangling yellow wattles of the male.
It is spectacularly plumaged, identical in male and female when perched but the female shows much more white in the primaries in flight. The head, neck, back, wings, and tail are iridescent black, with the rest of the body and the primary flight feathers being white. Juveniles are browner grey in plumage. The massive bill is red with a black band and a yellow frontal shield (the “saddle”). The legs and feet are black with pink knees. On the chest is a bare red patch of skin, whose colour darkens during breeding season.