how small are fleas

Fleas are very small insects, typically about 1.5 to 3 millimeters (mm) long, roughly the size of a grain of sand. Cat fleas, the most common type, are around 1 to 2.5 mm, while dog fleas and other types tend to be in the 2 to 4 mm range. They are wingless, dark brown or reddish-brown, and have laterally compressed bodies that help them move swiftly through the fur of their hosts. Their small size combined with quick movement makes them difficult to spot without close inspection.