Which Height Should I Make the Crib?

Mattress Placement

• When a baby is first transferred from a bassinet to a crib, usually between 2 and 3 months old, the mattress is normally placed at its highest level to make transferring the child in and out of the bed easy. If the crib is equipped with a side that moves up and down or a gate that folds down, it should be at least 9 inches above the mattress surface in the lowered position to prevent the child from falling over the side. When the side or gate is raised, it should be at least 26 inches above the support below the mattress.

Adjustment Guidelines

• As the child grows and becomes more active, the mattress should be adjusted. The first time the child sits up without assistance, lower the mattress to prevent her from tumbling out of the crib. Lower the mattress again when the child stands on her own and starts to develop climbing skills. When the child reaches a height of 35 inches, it is time for her to be removed from the crib and start sleeping in a toddler, child or twin size bed, as she is apt to climb out of the crib, even with the mattress in its lowest position.

Slats and Perimeter Space

• According to the U.S. Consumer Product Safety Commission, the slats that support the mattress should be no more than 2 3/8 inches apart to prevent the child's body or body parts from getting stuck if he is nimble enough to raise the mattress. A full size crib is 52 inches long and 28 inches wide. To ensure there is no room for the child to get his arms, legs or heads stuck in between the mattress and the crib frame, the mattress should be 51 3/4 inches long by 27 ¾ inches wide. If you can fit two fingers between the side of the mattress and the wall of the crib, the mattress is too small and needs replacing.

Tips and Hints

• If the childcare provider is more than 6 feet tall, he may find the height of the crib strains his back when caring for the child. Kneeling on a sturdy stool next to the bed eases the back pressure. To eliminate the need to purchase a regular bed when the child outgrows the crib, buy a crib that converts into a toddler bed that sits closer to the ground and has protective side slats to prevent falls from the bed.