Cost per ounce*
Class	Brand names	Calories (kcal per oz)	Carbohydrate source	Protein source	Indications	Powdered formula†	Ready-to-feed
Breast milk	—	20	Lactose	Human milk	Preferred for all infants	—	—
Term formula	Carnation Good Start; Enfamil with Iron; Similac with Iron	20	Lactose	Cow's milk	Appropriate for most infants	$0.14	$0.27
Term formula with DHA and AA	Enfamil Lipil; Good Start DHA & ARA; Similac Advance	20	Lactose	Cow's milk	Marketed to promote eye and brain development	0.16	0.30
Preterm formula	Enfamil 24 Premature; Preemie SMA 24; Similac 24 Special Care	24	Lactose	Cow's milk	Less than 34 weeks' gestation Weight less than 1,800 g (3 lb, 15 oz)	—	0.80
Enriched formula	Enfacare; Similac Neosure	22	Lactose	Cow's milk	34 to 36 weeks' gestation Weight 1,800 g (3 lb, 15 oz) or greater	0.19	0.32
Soy formula	Enfamil Prosobee; Good Start Soy; Similac Isomil	20	Corn-based	Soy	Congenital lactase deficiency, galactosemia	0.16	0.30
Lactose-free formula	Enfamil Lactofree; Similac Sensitive	20	Corn-based	Cow's milk	Congenital lactase deficiency, primary lactase deficiency, galactosemia, gastroenteritis in at-risk infants	0.16	0.30
Hypoallergenic formula	Similac Alimentum; Enfamil Nutramigen; Enfamil Pregestimil	20	Corn or sucrose	Extensively hydrolyzed	Milk protein allergy	0.25	0.37
Nonallergenic formula	Elecare; Neocate; Nutramigen AA	20	Corn or sucrose	Amino acids	Milk protein allergy	0.35	—
Antireflux formula	Enfamil AR; Similac Sensitive RS	20	Lactose, thickened with rice starch	Cow's milk	Gastroesophageal reflux	0.18	0.31
Toddler formula	Enfamil Next Step; Good Start 2; Similac Go and Grow	20	Lactose	Milk	Nine to 24 months of age	0.15	0.25