The Black-capped Chickadee has a black cap and bib with white sides to the face. Its underparts are white with rusty brown on the flanks. Its back is gray and the tail is normally slate-gray. This bird has a short dark bill of 8–9.5 mm (0.31–0.37 in), short rounded wings 63.5–67.5 mm (2.50–2.66 in), a moderately-sized tarsus of 16–17 cm (6.3–6.7 in) and a long tail at 58–63 mm (2.3–2.5 in). Total body length is 12–15 cm (4.7–5.9 in), wingspan is 16–21 cm (6.3–8.3 in) and body mass is 9–14 g (0.32–0.49 oz). Sexes look alike, but males are slightly larger and longer than females
The black-capped chickadee is found from coast to coast, from the northern half of the United States in the south, to James Bay, the southern edge of the Northwest Territories and the Yukon, and the southern half of Alaska in the north. In winter it may wander outside this range, both to the north and south. Its preferred habitat is deciduous woods or mixed (deciduous/coniferous) woods. It is also found in open woods, parks, and suburban areas. Habitat segregation is the principal factor that separates the Black-capped Chickadee from both the Boreal Chickadee in the north and the Chestnut-backed Chickadee in the Pacific northwest (these two species prefer strictly coniferous forests). Altitude also separates the Black-capped Chickadee from the (higher) Mountain Chickadee in the western mountains and the (lower) Carolina Chickadee in the Great Smokey Mountains.