The average age at which babies learn how to roll over on their own is approximately 6 months. While some babies are able to master this skill before they hit the 6-month mark, others take a bit longer than 6 months to reach this milestone.
Each baby grows and develop at his own pace. While it might take one infant slightly more time than most to develop in one particular area, he may end up being miles ahead of the curve in another. Once babies do learn how to roll over on their own, they are well on their way to sitting, crawling and eventually walking.