At 4 months, a baby consumes 6 to 8 fluid ounces of formula per feeding, for a total of about 30 fluid ounces per day, according to WebMD. A breast-fed baby consumes about 4 fluid ounces per feeding, for a total of 25 fluid ounces per day.
Babies going through growth spurts may require more breast milk or formula than usual. Breast-fed and formula-fed babies require different amounts of milk due to various factors; for example, babies metabolize breast milk and formula differently. Additionally, babies have more control over the amount of milk they consume when breast-feeding, which better enables them to stop eating when full.