Bed bugs are small insects that measure about the size of an apple seed. Adult bed bugs typically range from 4 to 7 millimeters (approximately 0.16 to 0.28 inches) in length. They have flat, oval-shaped bodies and are brown or reddish-brown in color. Nymphs (young bed bugs) are smaller, starting around 1.5 millimeters, and are translucent or whitish-yellow until they feed. Bed bug eggs are even smaller, roughly the size of a pinhead and pearly white. Despite their small size, adult bed bugs are visible to the naked eye but might be mistaken for other tiny insects.