Are male blue crabs bigger than female crabs?

Yes, male blue crabs are generally bigger than female blue crabs. The average size of a male blue crab is about 6 inches (15 cm) across the back, while the average size of a female blue crab is about 4 inches (10 cm) across the back. However, there is some overlap in size between the two sexes, and some female crabs can be larger than some male crabs.