How tall is a hermit crab?

The size of hermit crabs varies greatly among species. The smallest species, such as the pea crab (Pagurus bernhardus), can be as small as 0.5 inches (1.3 cm) long, while the largest species, such as the giant robber crab (Birgus latro), can grow to be over 2 feet (0.6 m) long and weigh up to 11 pounds (5 kg). Most hermit crab species, however, are between 1 and 3 inches (2.5 and 7.6 cm) long.