The tawny owl is a robust bird, 37–46 cm (15–18 in) in length, with an 81–105 cm (32–41 in) wingspan. Weight can range from 385 to 800 g (0.849 to 1.764 lb). Its large rounded head lacks ear tufts, and the facial disc surrounding the dark brown eyes is usually rather plain. The nominate race has two morphs which differ in their plumage colour, one form having rufous brown upperparts and the other greyish brown, although intermediates also occur. The underparts of both morphs are whitish and streaked with brown. Feathers are moulted gradually between June and December. This species is sexually dimorphic; the female is much larger than the male, 5% longer and more than 25% heavier.
The tawny owl flies with long glides on rounded wings, less undulating and with fewer wingbeats than other Eurasian owls, and typically at a greater height. The flight of the tawny owl is rather heavy and slow, particularly at takeoff. As with most owls, its flight is silent because of its feathers‘ soft, furry upper surfaces and a fringe on the leading edge of the outer primaries. Its size, squat shape and broad wings distinguish it from other owls found within its range; great grey, eagle owl and Ural owls are similar in shape, but much larger.