The true finches are small to medium-sized passerine birds in the family Fringillidae. Finches have stout conical bills adapted for eating seeds and often have colourful plumage. They occupy a great range of habitats where they are usually resident and do not migrate. They have a worldwide distribution except for Australia and the polar regions. The family includes species known as siskins, canaries, redpolls, serins, grosbeaks and euphonias. Many birds in other families are also commonly called "finches", including some species in the very similar-looking waxbills or estrildid finches (family Estrildidae) of the Old World tropics and Australia; several groups of the bunting and American sparrow family (Emberizidae); and the Darwin's finches of the Galapagos islands, now considered members of the tanager family (Thraupidae).
The smallest "classical" true finches are the Andean siskin (Spinus spinescens) at as little as 9.5 cm (3.8 in) and the lesser goldfinch (Spinus psaltria) at as little as 8 g (0.28 oz). The largest species is probably the collared grosbeak (Mycerobas affinis) at up to 24 cm (9.4 in) and 83 g (2.9 oz), although larger lengths, to 25.5 cm (10.0 in) in the pine grosbeak (Pinicola enucleator), and weights, to 86.1 g (3.04 oz) in the evening grosbeak (Hesperiphona vespertinus), have been recorded in species which are slightly smaller on average. They typically have strong, stubby beaks, which in some species can be quite large; however, Hawaiian honeycreepers are famous for the wide range of bill shapes and sizes brought about by adaptive radiation. All true finches have 9 primary remiges and 12 rectrices. The basic plumage colour is brownish, sometimes greenish; many have considerable amounts of black, while white plumage is generally absent except as wing-bars or other signalling marks. Bright yellow and red carotenoid pigments are commonplace in this family, and thus blue structural colours are rather rare, as the yellow pigments turn the blue color into green. Many, but by no means all true finches have strong sexual dichromatism, the females typically lacking the bright carotenoid markings of males.