The standard size of a full-size crib as of 2015 is 28 inches wide, plus or minus five-eighths of an inch, and 52 3/8 inches long, plus or minus five-eighths of an inch, according to the Consumer Product Safety Commission. This standard minimizes or prevents crib injuries and deaths.
The safest mattresses to use in full-size baby cribs are a minimum of 27 1/4 inches wide and 51 1/4 inches long, and they are not thicker than 6 inches. Mattresses meeting those dimensions help prevent suffocation and head entrapment. Paint for the cribs must not hold more than 0.009 percent lead.