How Many Ounces of Formula a Day Should a 5 Week Old Infant Eat?

by Lara Alspaugh

One of the biggest challenges new parents face is feeding their baby. Without an instruction manual and no absolute idea how much your baby should take, you might be concerned that she is not getting enough or is getting too much. Take these factors into account when deciding how much formula your little one should be taking at five weeks of age.


It is important to know how much your baby is eating and it's important that he get enough. Not getting enough formula can cause a baby to delay gaining weight--which is the goal at this point. Babies who are not eating enough can lose weight, have a decrease in energy and can become dehydrated. These are all causes for concern and would need immediate medical attention.


While every baby is different, a general rule of thumb is to multiply 2.5 by your child's weight to determine how many ounces of formula she needs. If your daughter weighs eight pounds, you should feed him around 20 ounces over a 24-hour period.
Keep in mind all babies are different and yours may eat more or less than that amount.

Time Frame

Babyies typically experience growth spurts around 14 days, three weeks, six weeks, three months and six months. During these periods of time, their consumption of formula may increase drastically. You may feel like your baby does nothing but eat--five weeks is very close to the typical six-week growth spurt so be prepared.


Because babies are so different it's important to have other parameters to determine if your baby is getting enough. If she is gaining weight, wetting around six diapers a day and experiencing periods of sleep and alert behavior, then it's likely your baby is getting enough formula.


If you feel that your baby is not eating enough formula, is acting lethargic, is not easily aroused or has a drastic drop in wet diapers from what has been his normm then you should see your baby's health care provider immediately.
There can be many reasons why a baby stops taking in formula and it's important to identify that reason as soon as possible.

About the Author

Lara Alspaugh is a registered nurse with a Bachelor of Science in nursing from Michigan State University. She is a faculty member at Lansing Community College in the nursing department. Her work can be found on and as well as many print magazines and newspapers.