A:Answer Hi, thanks for reaching out. The mattress size should be at least 27.25 inches wide x 51.625 inches long and should not exceed more than 6 inches thick. The mattress should be of such length and width that the gap between the mattress and the sides of the crib is not more than 1-3/16 inches when the mattress is pushed into the corner of the crib. This is for safety reasons, ensuring no gaps.
