Most babies transition to a crib somewhere between 3 and 6 months old, though the exact timing depends more on your baby’s development than a specific birthday. Some parents use a crib from day one, while others start with a bassinet or bedside sleeper and switch later. Either approach is safe as long as you follow current sleep guidelines. The key is knowing the signs that your baby has outgrown their current setup and making the crib environment as safe as possible.
Room Sharing vs. a Separate Nursery
The CDC recommends keeping your baby’s sleep area in the same room where you sleep for at least the first 6 months. Room sharing (not bed sharing) can reduce the risk of SIDS by as much as 50%. This doesn’t mean your baby can’t sleep in a crib during that time. A full-size crib in your bedroom works just as well as a bassinet. The protective factor comes from proximity, not the type of sleep surface.
After 6 months, moving the crib to a separate nursery is a common and reasonable step. Many families make the move earlier, around 4 months, especially if everyone’s sleep is suffering. If you do move your baby to another room before 6 months, a reliable baby monitor helps you stay aware. Place it 3 to 6 feet from the crib, and secure any cords against the wall with clips or covers so they’re completely out of reach.
Signs Your Baby Has Outgrown the Bassinet
If your baby sleeps in a bassinet, the transition to a crib isn’t optional once certain milestones hit. Rolling is the most urgent one. A baby who can roll from back to side or back to stomach has outgrown the narrow walls of a bassinet, which aren’t designed to be safe for a mobile infant. Other signs include:
- Pushing up on hands and knees. This gives a baby enough leverage to potentially tip or fall out of a shallow bassinet.
- Reaching the weight limit. Most bassinets are rated for 15 to 20 pounds. Check your specific model’s label.
- Looking cramped. If your baby’s head or feet are pressing against the sides, they need more space.
- Grabbing or climbing the sides. Any attempt to pull on the mesh or edges means it’s time to move.
Rolling typically starts around 4 months but can happen earlier. If your baby rolls even once, don’t wait for it to become consistent. Move them to the crib that day.
Using a Crib From Birth
There’s no minimum age for crib use. A full-size crib with a firm, flat mattress is a safe sleep surface from your baby’s first night home. Some parents prefer a bassinet early on because it’s smaller, portable, and easier to keep next to the bed. But if you’d rather skip the bassinet entirely, a crib in your room works fine.
Newborns sometimes seem lost in a full-size crib, and parents worry they won’t sleep as well in a larger space. In practice, babies adjust quickly. The crib’s interior dimensions are standardized at roughly 28 inches wide by 52 inches long, which provides plenty of room for growth through the toddler years.
Setting Up the Crib Safely
The sleep surface matters more than the timing. A firm, flat mattress is essential. It should fit snugly inside the crib frame with no gaps wider than two fingers between the mattress edge and the crib sides. Beyond the mattress, the crib should be empty. That means no blankets, no pillows, no stuffed animals, no bumper pads, and no weighted products of any kind.
Johns Hopkins Medicine specifically warns against wedges, positioners, and “special” sleep surfaces marketed to prevent SIDS. These products haven’t been shown to reduce risk and have, in rare cases, caused infant deaths. The same goes for fluffy comforters, sheepskins, and any item that could cover your baby’s face.
For warmth, use a sleep sack or wearable blanket instead of loose bedding. Keep the nursery temperature between 68 and 72 degrees Fahrenheit. A good rule of thumb: if the room feels comfortable to you in a T-shirt, it’s about right for your baby in a sleep sack.
Making the Transition Easier
If your baby has been sleeping in a bassinet next to your bed, moving to a crib can feel like a big change for both of you. A gradual approach helps. Start with naps in the crib during the day so your baby gets used to the space in shorter stretches. Once naps are going smoothly, move nighttime sleep to the crib as well.
Keeping the bedtime routine identical matters more than the location. Whatever sequence you use before sleep (feeding, changing, dimming lights, white noise) should stay exactly the same. Babies rely on these cues to wind down, and consistency signals that it’s time to sleep even though the surroundings are different. White noise can be especially helpful during the transition because it provides a familiar auditory backdrop regardless of which room your baby is in.
If you’re moving the crib to a separate room, some parents find it easier to do an intermediate step: place the crib in your bedroom first, let your baby adjust to the new sleep surface for a week or so, then move the crib to the nursery. This separates two changes (new surface and new room) so your baby only deals with one at a time.
Common Ages at a Glance
There’s no single “right” age, but here’s how timing typically breaks down. Babies who start in a bassinet usually move to a crib between 3 and 6 months, with rolling ability being the hard deadline. Babies who use a crib from birth skip the transition entirely. The move to a separate room commonly happens around 6 months, aligned with the room-sharing recommendation, though some families wait longer and some move sooner.
The most important thing isn’t hitting a specific week or month. It’s watching your baby’s development, respecting the weight and size limits of whatever sleep product you’re using, and keeping the crib free of anything that doesn’t belong there.