According to U.S regulations, a standard full-size crib is 30 inches wide and 54 inches long. A standard crib mattress is 52 by 28 inches. The adjustable railing must be 26 inches above the bottom mattress at its maximum height and 9 inches above the mattress support at its lowest.
The maximum space between vertical slats is 2? inches. Slats that are farther apart pose a serious safety risk, as an infant's head may easily become stuck. The corner posts must not rise more than one-sixteenth of an inch above the crib to prevent any clothing getting caught and creating a choking hazard.