Baby sitting laughing with mother
Development and Play

Your Baby’s 4- and 6-Month Milestones

June 8, 2026

Key takeaways: By 4 months, most babies chuckle, coo back, hold their head steady, and reach for toys. By 6 months, most laugh, blow raspberries, roll from tummy to back, and lean on their hands to sit. If your baby is missing milestones or losing skills, talk to your doctor.

Between 4 and 6 months, babies become more interactive and mobile. Here’s what to look for, based on the CDC’s updated milestone checklists.

Milestones by 4 Months

Social and emotional:

  • Smiles on their own to get your attention.
  • Chuckles (not yet a full laugh) when you try to make them laugh.
  • Looks at you, moves, or makes sounds to get or keep your attention.

Language and communication:

  • Makes sounds like “oooo” and “aahh” (cooing).
  • Makes sounds back when you talk to them.
  • Turns head toward the sound of your voice.

Cognitive:

  • Opens mouth when hungry if they see the breast or bottle.
  • Looks at their hands with interest.

Movement and physical:

  • Holds head steady without support when you’re holding them.
  • Holds a toy when you put it in their hand.
  • Uses their arm to swing at toys.
  • Brings hands to mouth.
  • Pushes up onto elbows or forearms when on tummy.

Milestones by 6 Months

Social and emotional:

  • Knows familiar people.
  • Likes to look at themselves in a mirror.
  • Laughs.

Language and communication:

  • Takes turns making sounds with you.
  • Blows “raspberries.”
  • Makes squealing noises.

Cognitive:

  • Puts things in their mouth to explore them.
  • Reaches to grab a toy they want.
  • Closes lips to show they don’t want more food.

Movement and physical:

  • Rolls from tummy to back.
  • Pushes up with straight arms when on tummy.
  • Leans on hands to support themselves when sitting.

From the author

From First Breath to First Birthday is my month-by-month guide to your baby’s first year, written as a NICU and postpartum nurse. My book follows your baby’s growth and development month by month, from the first hours after birth to the first birthday.

See the book on Amazon →

How to Support Development

  • Talk back and forth. Imitate your baby’s sounds and wait for a reply.
  • Read every day. Point to pictures and name them.
  • Floor time: lots of tummy time and play on a safe floor to practice rolling and reaching.
  • Offer toys just out of reach to encourage stretching and rolling.
  • Mirror play for self-discovery.
  • Limit time in containers like bouncers and seats.
  • Respond warmly to your baby’s cues.

When to Talk to Your Doctor

At 4 months, talk to your doctor if your baby:

  • Doesn’t watch things as they move.
  • Doesn’t smile at people.
  • Can’t hold head steady.
  • Doesn’t coo or make sounds.
  • Doesn’t bring things to mouth.
  • Doesn’t push down with legs when feet are on a hard surface.
  • Has trouble moving one or both eyes in all directions.

At 6 months, talk to your doctor if your baby:

  • Doesn’t try to get things within reach.
  • Shows no affection for caregivers.
  • Doesn’t respond to sounds around them.
  • Has difficulty getting things to mouth.
  • Doesn’t make vowel sounds or laugh.
  • Doesn’t roll over in either direction.
  • Seems very stiff or very floppy.

At any age: loss of skills is always a reason to call.

The Bottom Line

From 4 to 6 months, babies become chatty, giggly, and on the move. Lots of floor time and back-and-forth “conversation” support growth. Trust your instincts and ask if you’re concerned.

Want more support for your baby’s first year? My book, From First Breath to First Birthday, is available on Amazon.

Related Articles

Sources

  1. Centers for Disease Control and Prevention. Learn the Signs. Act Early.: Milestones by 4 Months; Milestones by 6 Months. https://www.cdc.gov/milestones
  2. Zubler JM, Wiggins LD, Macias MM, et al. Evidence-informed milestones for developmental surveillance tools. Pediatrics. 2022;149(3):e2021052138.
  3. Lipkin PH, Macias MM; Council on Children With Disabilities, Section on Developmental and Behavioral Pediatrics. Promoting optimal development: identifying infants and young children with developmental disorders through developmental surveillance and screening. Pediatrics. 2020;145(1):e20193449.
  4. Yogman M, Garner A, Hutchinson J, Hirsh-Pasek K, Golinkoff RM; Committee on Psychosocial Aspects of Child and Family Health; Council on Communications and Media. The power of play: a pediatric role in enhancing development in young children. Pediatrics. 2018;142(3):e20182058.

This article is for general education and is not a substitute for individualized medical advice. Always talk with your baby’s health care provider or your own provider about your specific situation. If you think your baby or you may have a medical emergency, call 911.

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