The answer is…IT DEPENDS.
Rolling is usually the first time that your little one will be able to change his position all by himself. Some parents notice that their babies seem to roll over when they are only a month or two old. Generally, this rolling is the result of a reflex that babies have when they are born. In this instance, if a baby’s head is turned when she is on her back, her body will turn in order to keep the head and body lined up. In other instances, babies may be wiggling and kicking so much on their back or belly that they roll themselves over without meaning to. Once they are a few months old, we see this “accidental” rolling less often because of the changes in baby’s body proportions and the way they move their weight when they are on their back or belly.
Some babies will roll as early as 3-4 months, while others will wait until they are 5-6 months old. When your baby will roll depends on how strong his back and belly muscles are, his motivation to move and explore his environment, and how well he likes being on his back or belly. The first few times he rolls, it may be accidental and your baby may be startled and upset by the movement. While startling, these early experiences will also help your baby start to learn about how he can move his body himself. In the past, babies seemed to learn to roll from their belly to back before they rolled to their tummy. Nowadays, it seems to be much more variable! Babies who love tummy time may be more likely to roll to their tummy from their back, while babies who are unhappy on their tummy may wiggle and twist until they figure out how to get off their belly. The more time your baby spends flat on her back on a firm surface and working on tummy time, the stronger her back and tummy muscles will be and the easier it will be for her to master the new skill of rolling.
By 6-7 months, we expect that babies are able to roll from their back to belly as well as belly to back. As with all movement, it is also important that we see baby rolling to both the right and left sides. When babies first learn a new skill, they will usually practice it over and over and over again. This is their way of fine tuning their movement and learning to make it the most efficient. During this time, it is not unusual to see a baby who tends to move in one preferred direction. Just be sure that within a few weeks of learning that new skill, you also see them working on the other direction. If your baby is struggling a bit, it is a great idea for you to help them practice so that they can master this movement. Whether your baby is rolling at 4 months or 6, remember that this is her first experience with changing her position all on her own, and it’s an exciting new skill to celebrate!