Although not highly contagious, common warts are caused by viruses and can be transmitted from person to person. They may occur anywhere on the body but are frequently seen on the hands, feet, and face (areas of frequent contact).

Warts are categorized by their location and appearance. On the soles of the feet they are called plantar warts. Around and under the fingernails or toenails they are periungual or subungual warts, respectively. The medical term verruacea vulgaris simply means "common wart". Flat warts, also known as verrucae planea juveniles, are small (pinhead size) warts with flat surfaces and are often seen in children. Common locations for flat warts include the face, forehead, arms, and legs. This type of wart is seen less often in adolescents and seldom in healthy adults.

The typical wart is a raised round or oval growth on the skin with a rough surface. Compared with the surrounding normal skin, warts may appear light, dark, or even (rarely) black. Most parents are familiar with the look of a typical wart and have little trouble in diagnosing the condition. However, unusual warts with smooth surfaces or flat warts in children may be more difficult for parents to recognize as warts. Common warts cause no discomfort unless they are in areas of repeated trauma.

Plantar warts are no different than the common wart but, because of their location on the soles of the feet, they can become extremely painful. Large numbers of plantar warts on the foot may cause difficulty running and walking and can be debilitating.

Warts around and under the fingernail are similar to the common wart, but much more difficult to cure.

The common wart may disappear spontaneously, usually within two years of its appearance. Because people generally consider warts unsightly and there is often a social stigma (which is usually most obvious amongst schoolchildren) associated with having warts, parents often seek treatment. Treatment of warts has improved significantly in the last 10 years, but even with effective treatment recurrence is not uncommon.