There's a range, but most are able to sit up (if you put them there) at 4 to 6 months.
When they can sit up on their own.
Babies can safely sit in a high chair when they are able to sit up on their own without support, usually around 6 months of age.
At 7 months old, your baby's muscles and coordination are still developing, which may make it challenging for them to sit up on their own. It is normal for babies to reach this milestone at different times, so continue to provide support and practice to help them strengthen their muscles and balance.
Babies develop at their own rate, but yes, a 4 month old may be able to sit with support. My 4.5 month old has learned to sit for short periods of time without support. I don't find this answer to be credible. Most babies do not sit on their own until 6-7 months of age. My son held his own neck up at only 2 days old and sat up on a boppy at 3 months old for 10 to 20 seconds at a time, but they fall left or right. At six months they learn to hold their toes or an object between their legs which keeps them balanced. Every baby does things at their own rate but a four month sitting up all by themselves is quite unbelievable.
Babies can safely sit in a high chair when they are able to sit up on their own, typically around 6 months of age.
Some babies sit up by 6 months. Apparently, however, not sitting up by 9 months isn't a big deal either. See the Related Link to a video regarding a baby's milestones - sitting included.
There are many 3 month old babies that can sit with support. You do need to make sure the baby can hold their head up.
Babies can safely sit in a highchair when they are able to sit up on their own without support, usually around 6 to 8 months of age. It is important to always supervise them while they are in the highchair.
Babies typically begin to sit up without support between 4 to 7 months of age. However, every baby develops at their own pace, so some may achieve this milestone earlier or later. It's important to provide a safe and supportive environment for babies to develop their strength and coordination.
Babies typically start sitting in a high chair around 6 to 9 months of age when they can sit up on their own and are ready to start eating solid foods.
Newborns cannot sit upright on their own and require support to sit up.
Babies can safely start using a high chair for meals and snacks when they can sit up on their own and support their head, usually around 6 months of age.