Ask just about any parent or caregiver and they’ll tell you: Sitting is a highly-anticipated baby milestone. Not only is it — let’s face it — adorable, but it’s also usually a sign that things are on track with your little one’s physical development. (It takes a lot of baby strength training to be able to sit up without help!)
So, when do babies start sitting up? “Most babies will begin to sit on their own with their hands in front of them at around 6 months,” says Dr. Brandon Smith, associate medical director of the Harriet Lane Clinic at Johns Hopkins in Baltimore — but that’s usually only the beginning. “There’s always a range and some babies may start earlier and some may need a little more time.”
According to Smith, in order for a baby to sit up completely hands-free, they need solid core strength. So while they’re working on their ab and back muscles, they’ll use their arms to sturdy themselves. Wondering when babies should be sitting up on their own and how the process typically unfolds? Here, experts offer advice on what to look for and when, along with when to call the doctor.
Key stages: When do babies typically start sitting up?
Developmental milestones occur over a range of time, and according to Dr. Sara Siddiqui, a pediatrician and clinical assistant professor in the Department of Pediatrics at NYU Langone’s Hassenfeld Children’s Hospital in New York, sitting is one that typically happens around 6 months of age. However, don’t expect your baby to be a sitting pro by their half-year birthday. Around this time, babies are almost always still using their hands for support.
“As their neck and core strengthen, they’ll be able to sit unassisted for longer periods of time, generally mastering the milestone at around 9 months.”
—Dr. Sara Siddiqui, pediatrician and clinical assistant professor at New York University
“At about 6 months, babies are generally sitting with support, meaning they’re leaning on their outstretched hands in what’s referred to as a tripod sitting pose,” Siddiqui explains. “As their neck and core strengthen, they’ll be able to sit unassisted for longer periods of time, generally mastering the milestone at around 9 months.”
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Age-by-age Guide: When babies learn to sit up independently
Here’s a look at when babies typically learn to sit up, according to experts:
- 2 months: “By about 2 months of age, neck and head control is usually showing significant improvement,” says Dr. Nick DeBlasio, a pediatrician at the Pediatric Primary Care Center at Cincinnati Children’s Hospital Medical Center in Cincinnati. “This is also the time when the head is able to be raised about 45 degrees when baby is lying flat on their stomach.”
- 4-5 months: At this point, head control is pretty much set. “Babies generally can support their upper body with their arms when lying on their stomach at 4 months,” DeBlasio notes. “This increase in core muscle strength is crucial to starting to sit up.” Rolling from stomach to back, then back to stomach may happen around this time, as well, as baby gets stronger.
- 6 months: This is typically the age babies sit up — but it likely will be super wobbly and require support from their hands in the form of a tripod position (also known as “early sitting”). According to DeBlasio, this is a sign that babies have mastered neck control (no bobbing around) and have started developing core muscle strength.
- 9 months: “An infant should be able to sit without support by 9 months,” DeBlasio says. “If a child isn’t doing this at this age, they should be seen by their health care provider.”
“One of the first physical prerequisites for sitting is neck control and having the ability to support their own head when you pick them up.”
—Dr. Brandon Smith, pediatrician
Essential skills for babies to sit up
According to Smith, there are a number of skills a baby needs to master before learning to sit on their own. These include:
- Neck stability.
- Ability to control and support their head.
- Upper body control.
- Truncal strength, such as bearing weight on straight arms during tummy time.
“Baby’s development works in a top down way, from head to toe,” he points out. “So, one of the first physical prerequisites for sitting is neck control and having the ability to support their own head when you pick them up.”
Making sure your child gets in a few minutes of tummy time a few times a day will help strengthen these muscles, bringing your little one closer to this baby milestone, according Siddiqui.
Practical tips to help your baby sit up
Forget the fancy walking gadgets and baby seats. Ultimately, the best thing parents and caregivers can do to help babies achieve fine motor and gross motor milestones, such as sitting, is to play with them as much as possible on the floor.
“Tummy time in infancy and floor time are extremely important for baby to develop strength in the appropriate way — from head and neck strength to upper body, upper shoulders and chest strength,” notes Siddiqui. “Truncal support and balance are learned skills that should be practiced with babies.”
“During tummy time, baby is lifting their abdomen off of the ground so they can then push back into a sitting or almost sitting position,” she continues, but adds that every family has their own set of variables to take into account.
“Each parent can only do what is convenient and safe at the time to help strengthen baby,” Siddiqui says. “For example, if an older sibling is running around, it’s hard to have baby on the floor exploring for long periods of time. Do the best that you can with what is available to you.”
When should you worry if babies are not sitting up?
According to Smith, children should be evaluated by their pediatrician if they’re not sitting by 9 months of age — particularly if they’re not showing any signs of doing so. “It’s important their pediatrician examines them, sees how other parts of their development is going and gives their input,” Smith says. “They’ll also look for other things in the child’s history that may be able to explain what’s going on or what next steps are needed.”
“An infant should be able to sit without support by 9 months. If a child isn’t doing this at this age, they should be seen by their healthcare provider.“
—Dr. Nick DeBlasio, pediatrician
In addition to discussing any concerns about delays in development with your child’s health care provider, Siddiqui also recommends downloading a free app by the Centers for Disease Control (CDC) called the Milestone Tracker. “Never hesitate to call your child’s pediatrician, but the app has helpful information about all developmental milestones from birth to age 5 years old.”
