At 9.75 inches, they are approximately the same size as a Hairy Woodpecker. Sexes are similar, showing a white patch at the base of the primary feathers, especially visible during flight. The bill is dark gray, the legs and feet are olive-gray, and the eyes are dull red. Male White-headed Woodpeckers have a red patch at the nape separating the white crown from the black back. Females show all-black napes.
Juveniles are somewhat more brown in color with white wing patches broken by black.
Both sexes have orange-red patches on the crown, although this may be more restricted or absent in females. The juvenal plumage is replaced by the adult plumage during early fall.