The Great Spotted Woodpecker is 23–26 centimetres (9.1–10 in) long, with a 38–44 centimetres (15–17 in) wingspan. The upperparts are glossy black, with white on the sides of the face and neck. A black line zigzags from the shoulder halfway across the breast (in some subspecies nearly meeting in the center), then back to the nape; a black stripe, extending from the bill, runs below the eye to meet this latter part of the zigzag line. On the shoulder is a large white patch and the flight feathers are barred with black and white. The three outer tail feathers are barred; these show when the short stiff tail is outspread, acting as a support in climbing. The underparts are dull white, the abdomen and undertail coverts crimson. The bill is slate black and the legs greenish grey.