When to Lower the Crib Mattress
Crib mattresses drop to keep your baby safely inside as they grow. Here’s exactly when to lower it, and why each step matters.
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Start high for a newborn
Use the highest mattress setting for a newborn. They can’t roll or push up yet, and the higher position saves your back when lifting them in and out many times a day.
Lower it when they can sit up
Once your baby can sit up unassisted - often around 5–8 months - lower the mattress to the middle setting. A sitting baby who’s still on the high setting can topple over the rail.
Lower it again when they pull to stand
When they outgrow the crib
Once the lowest setting no longer keeps them safely in - typically when they’re climbing out or reach about 89 cm (35 inches) tall - it’s time to move to a toddler bed (a convertible crib makes this easy). Follow your crib’s stated height and age limits.
Ready to choose?
We compared 10 cribs on safety, convertibility, build, value and design - full-size, convertible, mini and travel cribs, for every nursery and budget.