The typical Thoroughbred ranges between 15.2 to 17.0 hands (62 to 68 inches, 157 to 173 cm) high, averaging 16 hands (64 inches, 163 cm). They are most often bay, seal brown, chestnut, black, or gray. Less common colors, recognized in the United States include roan and palomino. White is very rare, but is a recognized color separate from gray. The face and lower legs may be marked with white, but white will generally not appear on the body. Coat patterns that have more than one color on the body, such as Pinto or Appaloosa, are not recognized by mainstream breed registries. Good quality Thoroughbreds have a well-chiseled head on a long neck, high withers, a deep chest, a short back, good depth of hindquarters, a lean body, and long legs. Thoroughbreds are classified among the "hot-blooded" breeds, which are animals bred for agility and speed and are generally considered spirited and bold.
Thoroughbreds that are born in the Northern Hemisphere are officially considered a year older on the first of January each year; those born in the Southern Hemisphere officially are one year older on the first of August. These artificial dates have been set to enable the standardization of races and other competitions for horses in certain age groups.