A baby can sleep in a full-size crib from day one. There’s no minimum age requirement. What matters is that the crib meets current federal safety standards and that the sleep environment is set up correctly. Most parents start with a bassinet or bedside sleeper for convenience during nighttime feedings, then move to a crib sometime between 3 and 6 months, but the crib itself is safe from birth.
Crib From Birth vs. Bassinet First
Both a crib and a bassinet are safe sleep surfaces for a newborn. The reason many families start with a bassinet is purely practical: it’s smaller, portable, and fits easily next to the bed for middle-of-the-night feeds. But if you want to place your newborn directly in a crib, that’s perfectly fine.
The American Academy of Pediatrics recommends room sharing (not bed sharing) for at least the first 6 months, ideally up to a year. A landmark study published in The Lancet found that infants who shared a room with an adult had roughly one-fifth the risk of sudden infant death compared to those sleeping in a separate room. That protection held even after researchers accounted for other risk factors. So if you’re using a crib from birth, placing it in your bedroom for those first several months is the safest setup.
When to Move From a Bassinet to a Crib
If you started with a bassinet, the transition to a crib typically happens between 3 and 6 months. The exact timing depends on your baby’s size and development rather than a fixed date on the calendar. Standard bedside bassinets hold 15 to 20 pounds, convertible models up to about 25 pounds, and smaller rocking or travel bassinets often max out at 15 pounds.
Beyond weight, watch for these milestones that signal the bassinet is no longer safe:
- Rolling over: Once your baby can roll from back to stomach, the shallow sides of a bassinet become a tipping hazard.
- Pushing up on hands and knees: Any independent movement that could shift the bassinet or bring the baby close to the edge means it’s time to switch.
- Sitting up: A baby who can pull to a seated position could topple out of a bassinet entirely.
Some babies hit these milestones as early as 3 months, others closer to 6. Check your specific bassinet’s weight and age limits, because exceeding either one is the clearest sign to make the move.
Setting Up a Safe Crib
The crib itself needs to meet the Consumer Product Safety Commission’s current standard, ASTM F1169-19 for full-size cribs. If you’re buying new, any crib sold in the U.S. will comply. If you’re using a hand-me-down, check that it wasn’t manufactured before 2011, when stricter federal rules took effect, and that it hasn’t been recalled. Drop-side cribs are no longer legal to sell or donate because of entrapment risks.
The mattress should be firm and fit snugly inside the crib frame with no gaps larger than two finger-widths between the mattress edge and the crib wall. Both full-size and non-full-size crib mattresses must pass a federal firmness test. A soft mattress that conforms to a baby’s face is a suffocation risk, so if you can press into the surface and it holds the impression, it’s too soft.
Inside the crib, the only thing that belongs is a fitted sheet. No blankets, pillows, stuffed animals, or sleep positioners. Crib bumpers, including padded bumpers, vinyl bumper guards, and vertical slat covers, are banned under the Safe Sleep for Babies Act, which took effect in November 2022. The one exception is non-padded mesh liners, which are not covered by the ban. Inclined sleepers angled more than 10 degrees are also banned as hazardous products.
Tips for a Smooth Transition
Babies who’ve grown accustomed to a bassinet sometimes resist the switch to a larger crib. The open space can feel unfamiliar. A few strategies help ease the adjustment.
Start with naps. Putting your baby in the crib for daytime sleep first lets them get used to the new space while you’re awake and nearby. Once naps are going smoothly, move nighttime sleep to the crib as well. Some parents place the crib sheet in their own bed for a night beforehand so it carries a familiar scent, though this is anecdotal rather than studied.
Keep the rest of the bedtime routine identical. If you normally feed, read, and then put the baby down, do exactly that. The crib is the only variable that should change. Consistency in everything else signals to your baby that this is still sleep time, just in a different spot. If you’ve been room sharing, you can keep the crib in your bedroom at first and move it to the nursery later as a separate step.
When to Move Out of the Crib
Most children transition from a crib to a toddler bed between 18 months and 3 years old. The AAP gives two specific benchmarks for when a child has outgrown their crib: they’re taller than 35 inches, or the crib railing hits at the middle of their chest when they’re standing. Either scenario makes it easy for a toddler to climb or fall over the rail.
The most obvious real-world sign is repeated escape attempts. If your toddler is regularly climbing out, the crib is no longer preventing falls. It’s creating them. At that point, switching to a toddler bed or a mattress on the floor is the safer option, even if your child hasn’t hit the height threshold yet.