Most babies are ready to sleep in a crib somewhere between 3 and 6 months old, though some start from day one. The timing depends on whether your baby has been sleeping in a bassinet first and how quickly they outgrow it. A crib is safe from birth, so there’s no “too early,” but there is definitely a “too late” when it comes to moving out of a bassinet.
Why the Timing Matters
Bassinets are designed for newborns and young infants. They typically have a weight limit of 15 to 20 pounds, and once your baby hits certain physical milestones, the bassinet becomes a safety hazard. A baby who can roll over, push up on their hands and knees, or pull themselves up by grabbing the sides of a bassinet could tip it or fall out. At that point, the move to a crib isn’t optional.
If your baby has been sleeping in a crib from the start, this transition doesn’t apply to you. Cribs are built for long-term use from birth through toddlerhood, typically until somewhere between 18 months and 3 years old, when a child can climb out or no longer fits comfortably.
Signs Your Baby Has Outgrown the Bassinet
Some signs are physical milestones, and others are limits set by the manufacturer. Your baby needs to move to a crib if any of the following are true:
- Rolling over. Even rolling in one direction means the bassinet walls may not be tall or sturdy enough to contain your baby safely.
- Sitting up or pushing up on hands and knees. This raises your baby’s center of gravity and creates a tipping risk.
- Pulling up on the bassinet sides. This is the clearest sign your baby could fall out.
- Reaching the weight, height, or age limit. Every bassinet has manufacturer limits printed in the manual. Check yours, because they vary.
Most babies hit one of these milestones between 3 and 6 months. Some get there earlier. If your baby is bumping into the sides frequently, waking up more often because they can’t stretch out, or seems physically cramped, those are also practical reasons to make the switch even before a hard safety threshold is crossed.
Room Sharing and Crib Placement
The American Academy of Pediatrics recommends that babies sleep in the same room as their parents for at least the first 6 months, and ideally for the full first year. This doesn’t mean the same bed. It means placing your baby’s crib, portable crib, or play yard in your bedroom, close to where you sleep.
The first 6 months are the most critical window because rates of SIDS and other sleep-related deaths are highest during that period, particularly in bed-sharing situations. Room sharing on a separate surface reduces this risk. So if your baby outgrows a bassinet at 4 months, the simplest approach is to put the crib in your bedroom rather than moving the baby to a nursery right away. You can transition to a separate room after 6 months, or whenever you and your baby are sleeping well with the arrangement.
Setting Up a Safe Crib
According to the Consumer Product Safety Commission, a safe crib has a firm, tight-fitting mattress with no gaps between the mattress and the crib walls. Slats should be no more than 2⅜ inches apart, roughly the width of a soda can. All screws, brackets, and hardware should be secure with nothing missing, loose, or broken. Corner posts should be nearly flush with the top of the end panels (no taller than 1/16 of an inch) so clothing can’t catch on them.
Don’t add a mattress pad or topper. The extra cushioning creates a suffocation risk. The crib mattress should feel firmer than what you’d find comfortable for yourself, and that’s by design. Keep the crib bare: no pillows, no blankets, no stuffed animals, no bumper pads. Just a fitted sheet on a firm mattress.
How to Make the Transition Easier
If your baby has been sleeping in a snug bassinet, the crib will feel enormous to them. A few strategies can smooth the adjustment.
Start with naps. Let your baby take one or two daytime naps in the crib before switching nighttime sleep over. The first naps of the day tend to be easiest because sleep pressure is high and your baby is less likely to fight a new environment. Once daytime naps are going well, move nighttime sleep to the crib too.
Place your baby in the crib at an angle rather than dead center. Positioning them kitty-corner, with their head near the rail closest to the wall and feet toward the opposite corner, makes the space feel less vast. This small adjustment can help a baby who’s used to the close walls of a bassinet feel more settled.
Keeping Things Familiar
Babies rely heavily on consistency. Using the same type of sheet you had in the bassinet gives your baby a familiar texture and smell. A white noise machine can also bridge the gap, especially if your baby associated the sound with sleep in their previous setup. Keep the room cool and dark, matching whatever conditions your baby slept well in before.
If you’re moving the crib to a separate room at the same time, consider splitting the change into two steps. First, get your baby sleeping in the crib while it’s still in your bedroom. Once that’s comfortable, move the crib to the nursery. Changing the sleep surface and the room at the same time can be a lot for some babies, though plenty of families do both at once without issues.
Babies Who Start in a Crib From Birth
There’s no rule that says you need a bassinet first. A full-size crib meets all safe sleep guidelines from day one, and some families prefer to skip the bassinet entirely. The main advantages of a bassinet are portability and size. They’re easy to move between rooms during the day and fit next to your bed in tight spaces. But if your bedroom can accommodate a crib, or if you have a portable crib or play yard that meets safety standards, your newborn can sleep there from the start.
The key is that whatever surface your baby sleeps on is firm, flat, and free of soft bedding. Whether that’s a bassinet for the first few months or a crib from birth, the safety principles are the same.