Amounts at 4 months match the 3-month range, but two new questions often come up. The first is solids: current guidelines place the start between 4 and 6 months, never before 4 months, and one of the readiness signs is that milk alone no longer seems to satisfy your baby's appetite. The second is sleep: around 4 months, sleep cycles mature and many babies go through a regression lasting 2 to 6 weeks, with more night wakings that aren't always about hunger.
Splitting bottles at 4 months
Five bottles a day from the 3-4 month row come to roughly 25-30 oz (750-900 ml) over 24 hours.
The rule of thumb from the main guide (NHS) still applies: 150-200 ml of formula per kilogram of body weight per day, until around 6 months. Example only: a baby who weighed 6 kg would need about 900-1200 ml a day by this rule. Swap in your baby's real weight, or use the calculator on the main how-much-milk page.
If you do start solids with your pediatrician's agreement, they come on top: milk stays the main food until age 1.
Signs to watch at 4 months
- Hunger or comfort at night: active, long feeding and settling full point to hunger; barely eating and calming as soon as you pick them up point to comfort.
- Fullness cues: turning away, closing the mouth, relaxing. No need to finish the bottle.
- Readiness for solids: steady head, sitting with support, interest in your plate, tongue-thrust reflex fading.
See your pediatrician if night wakings come with fever, unusual crying or loss of appetite, or if wet diapers drop below 3 in 24 hours. Ambrette logs bottles and, later, each new food.
Frequently asked questions
Is my 4-month-old ready for solids?
Maybe. Solids can start between 4 and 6 months, never before 4 months, once your baby holds their head steady, sits with support, shows interest in food and the tongue-thrust reflex is fading. Confirm the timing with your pediatrician.
My 4-month-old wakes at night again. Do they need more milk?
Not necessarily. Around 4 months, sleep matures into structured cycles and many babies go through a regression. If your baby feeds actively and settles full, it's more likely hunger; if they barely eat and resettle when picked up, comfort is the need.
Should I go beyond 6 oz per bottle at 4 months?
The guide for 3-4 months is 5 to 6 oz (150-180 ml) per feeding. If your baby still seems hungry after a bottle, you can offer a little more, following their cues, and talk to your pediatrician if appetite changes a lot.
Sources
- Centers for Disease Control and Prevention (CDC), How Much and How Often to Feed Infant Formula.
- American Academy of Pediatrics (HealthyChildren.org), Amount and Schedule of Baby Formula Feedings.
- World Health Organization (WHO), Infant and young child feeding.
- American Academy of Pediatrics (HealthyChildren.org), Baby Sleep.
