The time should be determined according to the size of the crab.

Whole live crabs need to be boiled first, then steamed over high heat for about 5 minutes, then switch to low heat to continue, crabs under 3 taels should continue to be steamed for about 10 minutes, those weighing 3 to 4 taels should continue to be steamed for about 12 minutes, and those weighing more than 4 taels should continue to be steamed for about 15 minutes. Usually, for every 1-two increase in weight, the steaming time will increase by about 2 minutes. In short, the exact time for steaming crabs needs to depend on the size of the crab.