The Pine Grosbeak is a large and plump, heavy-chested finch with a round head. Its bill is thick and conical, but much stubbier than in other finch species.

This species is one of the largest species in the true finch family. It measures from 20 to 25.5 cm (7.9 to 10.0 in) in length and weighs from 52 to 78 g (1.8 to 2.8 oz), with an average mass of 56.4 g (1.99 oz). The pine grosbeak's wingspan is 13.0 in (33 cm). Among standard measurements, the wing chord is 10.2 to 11.6 cm (4.0 to 4.6 in), the tail is 7.8 to 9.5 cm (3.1 to 3.7 in), the bill is 1.4 to 1.65 cm (0.55 to 0.65 in) and the tarsus is 1.9 to 2.3 cm (0.75 to 0.91 in).Adults have a long forked black tail, black wings with white wing bars and a large bill. Adult males have a rose-red head, back and rump, They also possess black wings and tail, with a conical beak. Adult females are olive-yellow on the head and rump and grey on the back and underparts. Young birds have a less contrasting plumage overall, appearing shaggy when they moult their colored head plumage.