The Eurasian eagle-owl is a very large bird, smaller than the golden eagle ("Aquila chrysaetos"), but larger than the snowy owl ("Bubo scandiacus"), despite some overlap in size with both species. It is sometimes referred to as the world's largest owl, although Blakiston's fish owl ("B. blakistoni") is slightly heavier on average and the much lighter weight great grey owl ("Strix nebulosa") is slightly longer on average. Heimo Mikkola reported the largest specimens of eagle-owl as having the same upper body mass, , as the largest Blakiston’s fish owl and attained a length around longer. In terms of average weight and wing size, the Blakiston’s is the slightly larger species seemingly, even averaging a bit larger in these aspects than the biggest eagle-owl races from Russia. Also, although shorter than the largest of the latter species, the Eurasian eagle-owl can weigh well more than twice as much as the largest great grey owl. The Eurasian eagle-owl typically has a wingspan of , with the largest specimens possibly attaining . The total length of the species can vary from . Females can weigh from , and males can weigh from . In comparison, the barn owl ("Tyto alba"), the world's most widely distributed owl species, weighs about 500 g (1.1 lb) and the great horned owl ("B. virginianus"), which fills the eagle-owl's ecological niche in North America, weighs around 1.4 kg (3.1 lb).