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U.S. regulations define a full-size crib as one whose interior dimensions are 28 ± 5⁄8 inches (71 ± 1.6 centimeters) in width and 52 3⁄8 ± 5⁄8 inches (133 ± 1.6 centimeters) in length.* Non-full-size cribs may be larger or smaller, but must be rigid and must not have mesh sides. Compact and portable cribs are often 26¼ inches by 39½ inches.
The standard full-size crib mattress is 27¼ inches by 52 inches, and the crib 30 inches by 54 inches.
Voluntary standards set by the ASTM and the Juvenile Products Manufacturers Assn. require that the openings between slats be no greater than 2⅜ inches, so that babies' heads can’t be caught. The cornerposts also may not rise more than 1/16 inch above the side unless they rise at least 16 inches; a baby could hang by catching clothing on protruding posts.
Safety standards for cribs assume a child less than 35 inches high, and under the age of 2. If cribs are used for taller or older babies, the babies run the risk of falling out.
Cribs should not be placed near dangling window cords (to avoid hanging). Mattress covers should not be improvised out of plastic film (to avoid suffocation). Loose teething rails should be replaced.
Crib sheets are 28 inches by 52 inches (because nowadays they are usually fitted sheets), and crib blankets, about 45 inches by 60 inches.
The 30 inches by 54 inches size was established before 1900, but at that time a larger size, 40 inches by 60 inches, was also sold.†
*The actual language allows a bit more tolerance:
"Within a range of ± 5.1 cm (± 2 in.) of the following interior dimensions: The interior dimensions shall be 71 ± 1.6 cm (28 ± 5⁄8 in.) wide as measured between the innermost surfaces of the crib sides and 133 ± 1.6 cm (52 3⁄8 ± 5⁄8 in.) long as measured between the innermost surfaces of the crib end panels, slats, rods, or spindles. Both measurements are to be made at the level of the mattress support spring in each of its adjustable positions and no more than 5 cm (2 in.) from the crib corner posts or from the first spindle to the corresponding point of the first spindle at the other end of the crib."
† 1895 Montgomery Ward catalog.
The Consumer Products Safety Commission has a valuable website on crib safety:
16 CFR Parts 1219, 1220, 1500, et al. Full-Size Baby Cribs and Non-Full-Size Baby Cribs: Safety Standards; Revocation of Requirements; Third Party Testing for Certain Children’s Products; Final Rules. Federal Register / Vol. 75, No. 248 / Tuesday, December 28, 2010. Access at
ASTM F 1169–10, Standard Consumer Safety Specification for
Full-Size Baby Cribs.
ASTM F 406–10a, Standard Consumer Safety Specification for Non-Full-Size Baby Cribs/Play Yards.
These ASTM standards are incorporated by reference in the Federal Regulation.
Canada: Health Canada’s crib standard, SOR/86–969.
Europe: European standard EN 716.
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Last revised: 3 January 2013.