By six months, most babies can roll from tummy to back, use their hands to support themselves while sitting, and make back-and-forth sounds with you. These milestones appear on the CDC’s updated checklist, which was redesigned in 2022 so that each item reflects what at least 75% of babies can do at a given age. That threshold means most six-month-olds will hit these markers, but it also means a quarter of typically developing babies may not yet, so the list works best as a conversation starter with your pediatrician rather than a pass-fail test.
Movement and Motor Skills
The signature gross motor milestone at six months is rolling from tummy to back. Many babies figure out back-to-tummy rolling around the same time, but tummy-to-back usually comes first because the arm push-off is easier in that direction. You’ll also notice your baby pushing up with straight arms during tummy time, which builds the shoulder and core strength needed for crawling later.
Sitting is in progress but not independent yet. A six-month-old typically leans on their hands for support while sitting, creating a little tripod shape. They can hold this position for short stretches, but they’ll topple if they reach for something or get distracted. Surrounding them with a pillow or sitting close by keeps practice safe.
Fine motor skills are developing quickly, too. Babies at this age start transferring objects from one hand to the other, a coordination step that looks simple but requires both sides of the brain to work together. Their grasp shifts from a full-fist grip to a “raking” motion, where they use their fingers (minus the thumb) to drag small items toward their palm. You’ll see this when they try to pick up a piece of cereal or grab at a tag on a toy.
Communication and Language
Six-month-olds aren’t forming words, but they’re building the raw material for speech. Expect repetitive sounds like “ooh,” “aah,” and “ba-ba.” One of the more fun milestones on the updated CDC checklist is blowing raspberries, which exercises the lips and tongue in ways that matter for later consonant sounds. Babies at this age also make squealing noises, experimenting with pitch and volume.
The social side of language is just as important. Your baby should take turns making sounds with you. You talk, they babble, you respond, they babble again. This back-and-forth pattern is early conversational practice. Babies also respond to changes in your tone of voice. A sharp “no” will make most six-month-olds pause or look up, even though they don’t understand the word itself. Turning toward a new sound, whether it’s a dog barking or a door closing, shows that their auditory attention is developing normally.
Social and Emotional Behavior
Around six months, babies clearly know familiar people and react differently to strangers. You might notice your baby reaching for a parent or caregiver while pulling away from someone they don’t recognize. This distinction is a healthy sign of social memory forming.
Mirrors become fascinating at this age. Babies like to look at themselves, smiling at and reaching toward their reflection. They don’t understand it’s them yet (that comes closer to 18 months), but the visual feedback holds their attention. Laughing is also a confirmed six-month milestone. Not just a brief chuckle, but genuine belly laughs in response to peekaboo, funny faces, or tickling.
Cognitive Skills
A six-month-old explores the world primarily through their mouth. Putting things in their mouth to investigate texture, shape, and taste is expected and developmentally important, not just a habit to discourage. They also reach purposefully for toys they want, rather than only swatting at whatever happens to be nearby. This intentional reaching shows that the brain is connecting “I see that” with “I want that” and “here’s how to get it.”
Another new cognitive milestone is closing their lips to show they don’t want more food. This is early decision-making. Your baby is processing a preference and communicating it through a physical action, which is more sophisticated than it looks.
Sleep at Six Months
Most six-month-olds need about 10 to 11 hours of sleep at night plus three daytime naps. Each nap runs roughly one to two hours, though the third nap of the day is often shorter, sometimes just 30 to 45 minutes. Total sleep across 24 hours typically lands between 13 and 15 hours. Some babies are already starting to consolidate into two naps, but three is still common and perfectly normal at this age.
Signs Your Baby Is Ready for Solid Foods
Six months is the age most pediatric guidelines recommend introducing complementary solid foods alongside breast milk or formula. But age alone isn’t the deciding factor. Your baby should also be able to hold their head up steadily, sit with minimal support, and bring hands or toys to their mouth. Watch for interest cues: leaning toward food when they see it and opening their mouth wide. Equally important is the ability to show fullness by leaning back or turning away.
There’s also a physical change happening inside the mouth. Around this time, most babies lose the tongue-thrust reflex that automatically pushes food out. Instead, they start using their tongue to move food from front to back for swallowing. If your baby still pushes everything out with their tongue, they may need another week or two before solids click.
What to Watch For
Because the CDC’s milestone list is calibrated to what 75% of babies can do, a baby missing one item isn’t necessarily delayed. But missing several milestones, or losing skills they previously had, is worth raising with your pediatrician sooner rather than later. The AAP specifically chose the 75% threshold to discourage a “wait and see” approach. If something seems off, asking for a developmental screening with a validated tool is a reasonable next step, not an overreaction.
Specific things that warrant attention at six months include not rolling in either direction, not reaching for objects, not responding to sounds or voices, showing no interest in people’s faces, and making very few or no vocal sounds. Stiffness in the legs or trunk, or the opposite, an unusually floppy quality when you pick your baby up, can also signal that a closer look is helpful.