What are the correct crib mattress dimensions?
A standard bed has outside dimensions of 28 inches by 52 inches. To ensure a snug fit, the crib mattresses must be at least 27 1/4 “wide by 51 5/8” long, and no thicker than 5 “. However, some exceed this number by about a quarter of an inch to ensure an extra tight fit, especially in the corners. Since mattresses have some sag, you can squeeze them into a crib, even if they are slightly larger than the inside of the crib. There is also such a thing as a mini cot; If you want to buy a mini crib these mattresses must be 24 “by 38”. Make sure you don’t confuse mini crib mattresses and standard crib mattresses as they are not interchangeable.