How Much Milk Does My Baby Need?

By Summer, RNC, BSN, Breastfeeding Educator

Are you wondering how much milk your baby needs? Or how much your baby's stomach can hold, and how much they can drink in one session? Read on to find these answers and how to easily calculate the amount of milk your baby requires.

When your baby is born, their stomach is about the size of a marble and grows about the size of a marble daily. A newborn’s stomach can hold about a teaspoon of colostrum at birth. These super-concentrated drops of milk that your body first produces are quickly metabolized, and because your newborn’s tummy can hold so little volume, it may seem that they are always hungry. Just like a hummingbird, needing so much energy but no place to store it, newborn babies must eat almost constantly. The caloric content of your breast milk and formula is about 20 calories per ounce. The caloric content of colostrum is practically three times this amount, at 60 calories per ounce, but that is still only about eight calories per teaspoon. So your baby gets only eight calories at every breastfeeding session! This may explain why newborns need to eat so often. And your body also needs this frequent stimulation to begin breastmilk production. The two work together beautifully.

Nourished by this colostrum, your baby's stomach will grow to the size of a ping pong ball over the next few days and can hold about an ounce. When your milk comes in fully, your baby’s stomach will grow to the size of an egg and can hold about two ounces at a time, which will be metabolized in about three hours. After that, your baby will begin gaining weight, and your milk supply will increase to meet the increase in their caloric need.  Your baby's stomach will hold about three ounces by the one-month mark.

How many ounces should a baby eat?  

Your baby's metabolic rate determines your baby's caloric needs. Metabolism is regulated by weight and activity level. You will find many general guidelines based on age, in which an average weight and average activity level amongst all babies of the same age are considered.   The USDA recommendations used by The Women, Infants, and Children Program (WIC) found in their Infant Nutrition and Feeding Guide states that your baby needs about 500 calories daily for the first three months. If you consider that each ounce of breast milk or formula contains 20 calories, you will need to feed your baby eight feedings of just over 3 ounces to get in 500 calories a day. Since these guidelines are set to represent the entire population, there is plenty of room for smaller babies to fall through the cracks. A healthy newborn can weigh between six and nine pounds, and recommendations based on age may not accurately reflect your baby’s needs. Another approach is determining how much your baby needs based on weight. The American Academy of Pediatrics (AAP) recommends in their healthychildren.org publications to feed your baby two and a half ounces or 50 calories for every pound of body weight. According to these guidelines, an eight-pound baby would need 20 ounces of breast milk or formula daily. Either way, this is eight feedings of just over two and a half ounces. If you use weight to determine how much your baby needs, then as your baby grows, her weight gain will reflect an increase in the total ounces they need.

Along with these general guidelines, we monitor wet and dirty diapers with your baby’s weight gain and growth to determine if you are meeting your baby’s needs. Use the chart below as a reference only, and listen to your baby. Whether you are exclusively breastfeeding or bottle-feeding, anticipating their needs can help you learn to recognize your baby’s feeding cues.

   Age                    per Feeding       per Day

1 day  1 teaspoon       1 oz

       5 days              1 oz                     8 oz

                 10 days           2 oz                    16 oz            

    1 month – 3 months      3 oz                    24 oz

How do I calculate how much milk my baby needs?

Your newborn will lose weight until your milk comes in. By the two-week mark, they should weigh more than they did at birth and steadily gain to triple that by six months. Learn how to calculate how much breast milk or formula your baby needs based on their weight, and you will be assured that you are meeting their needs as they grow. To calculate how much milk your baby needs, you will need to know their weight in pounds. To find your baby’s weight in pounds, divide the ounces by 16 because there are 16 ounces in each pound. Then, add the results to the pounds and multiply by two and a half ounces.

Pounds + Ounces / 16 = Weight X 2.5 Ounces

For example, an 8lb 8oz baby would need about 16 oz of milk daily in eight feedings of just over two and a half ounces each.

   6 lb + 8 oz /16 = 6.5 lb X 2.5 oz = 16 oz/day

                              16 oz / 8 feedings = 2 oz /feeding                     

For metric, multiply weights in kilograms by 2.2 to find pounds and ounces by 30 to find milliliters.

                    2.954 kg  X 2.2 lb = 6.5 lb X 2.5 oz = 16 oz /day

                    16 oz X 30 ml = 480 ml / 8 feedings = 60 ml

What is the minimum amount of milk a baby needs?

Meeting a baby’s needs will provide them enough energy for daily life and calories left over to grow. And grow they will - your baby will grow about an inch taller every month, and your baby's brain and head will grow 80% of adult size by age two. The size of your baby's head and their length and weight are measurements used to confirm that your baby’s needs are being met. Compared with those of others of the same age, your baby's measurements will fall into a category of concern if your baby’s needs are not being met. Because breast milk is 90% water and is your baby’s only source of hydration, another good indication that your baby is getting all they need is six to eight wet diapers a day. Breastfeeding mothers concerned about their supply should not hesitate to pump and verify the amount. If you exclusively breastfeed, wait about an hour after nursing to sneak in a pump, and your supply will replenish before the baby eats again. If your baby is not gaining weight well, try breastfeeding on one breast only or for 5 – 10 minutes longer. Feeding on one breast only or waiting longer before switching to the other breast will help your baby gain weight because there is a higher fat content in the breast milk at the end of the feeding. We call this the HINDMILK, and a little more hindmilk at every feeding can go a long way. 

Conclusion

Follow age-based guidelines or use the weight-based method to determine how much milk your baby needs and how many ounces your baby should eat. As you learn to recognize your baby's feeding cues, these guidelines, along with your baby’s weight and measurements, will help you realize if there are any issues. As your baby grows, so will their caloric needs. If you are struggling with a low milk supply, contact us here at Leva for advice from a lactation consultant.