What Is a Standard Crib Mattress Size?

By Erica Loop
Your baby's crib mattress should provide both comfort and safety.
Your baby's crib mattress should provide both comfort and safety.

Choosing a crib mattress isn't the same as buying a mattress for yourself. Instead of flopping down on potential picks to test their comfort level, you must find a mattress that safely fits your baby's crib. The American Academy of Pediatrics states on HealthyChildren.org that parents and caregivers should always ensure the baby furniture they choose meets the most current safety requirements.

Between the Crib

The Consumer Products Safety Commission defines the standard size for a full-size baby crib as 28 inches wide by 52 3/8 inches long, plus or minus 5/8 inch for both width and length. At a minimum, the mattress should be 27 1/4 inches wide by 51 1/4 inches long, and it should be no thicker than 6 inches. A full-size crib, it explains, is one that is designed to provide sleeping accommodations for an infant and is intended for use in the home, a child care facility, a family child care home or in places of public accommodation affecting commerce.

Checking for Fit

At best, the mattress should press up against the crib's rails so that there is no gap or space between the side of the mattress and the side of the crib. A gap the width of two adult fingers is excessive, according to the commission.

About the Author

Based in Pittsburgh, Erica Loop has been writing education, child development and parenting articles since 2009. Her articles have appeared in "Pittsburgh Parent Magazine" and the website PBS Parents. She has a Master of Science in applied developmental psychology from the University of Pittsburgh's School of Education.