4 Oz Of Breast Milk Equals How Much Formula? (Calculating Amount Of Formula Baby Needs)

When calculating how much 4 oz of breastmilk can be made from the formula, you only need to add 2 scoops of formula with 4 ounces of water to make an equal amount. You need to know how much milk to feed your baby per feeding, which can be calculated by knowing your baby’s weight and age. 6 ounces of formula is perfect for two feedings of a baby weighing 8.25 pounds. For any reason, don’t think of mixing breastmilk with formula as it can ruin the consistency of milk. If you want to, feed breastmilk first, then go with the formula. 

There could be various reasons for choosing to give your child formula milk, such as lesser milk production, some medical condition, milk allergy, same-sex parents, or some other issue making it impossible to arrange breastmilk.

It’s easier for some parents to switch to formula when their munchkin has turned 6 months of age, and they can finally switch over to the formula. 

But it can be confusing for breastfeeding mothers to switch over to formula bottles. If you’ve already set a routine and the amount of feeding to your little one, you need to know how much formula can be made, equivalent to 4 oz of breastmilk. Most parents struggle with equating the ounces of breastmilk with formula and making sure their baby isn’t overfed.

There’re ways to calculate how many ounces of breast milk equals formula so you can feed your baby the exact amount of milk. Switching to formula feeding has never been this easy when you know how much to feed and when to feed. Let’s find out how you can do so!

Amount of breast milk you can fit in a bottle

A new mom is preparing breast milk in different bottles for her newborn baby's upcoming feeding schedule

Before we jump right into calculating how many scoops of that formula powder you need to make a quantity of 4 ounces of breast milk, it’s essential to know how much milk your baby should be taking each feeding. 

It’s easier to convert breast milk to a bottle per feeding. Once you know this, you’ll know how many bottles 4 ounces make and if that’s sufficient for one feeding or two?

Step 1

A lot depends on your baby’s current weight, and it totally decides the amount of milk they should be feeding on right now and how many feedings per day they require to be not overfed. 

One pound equals 16 ounces. You can convert extra ounces into pounds by dividing the ounces by 16. If your baby weighs 8 pounds 4 ounces, that’ll equal 8.25 pounds. 
If you use kilograms to weigh your baby, multiply by 2.2 to get it in pounds. So, a baby weighing 3.74 kilograms converts to 8.25 pounds. 

I know this might be a bit taxing. But if you’re able to spend some time calculating this, you can avoid overfeeding your baby, which makes them so uncomfortable.

Step 2

It’s recommended to feed your baby 2.5 ounces of breast milk daily per pound of bodyweight for babies up to 10 pounds.

Now that you know your baby’s weight in pounds multiply that by 2.5. A baby weighing 8.25 pounds into 2.5 recommended ounces of milk makes it 20.6 ounces, which they need in one day. 

Your baby should be drinking about 20.6 ounces of breast milk in a day (24 hours) to be healthy and not overfed.

Step 3

We have come this far, and now is the time for the final step to know how many ounces of breast milk fill up a bottle for a baby weighing 8.25 pounds (3.74 kg). 

Now, you need to divide the total number of ounces per day by how many feedings you give your baby in one day. A newborn or young infant should be eating every 3 hours, which comes to 8 times per day. 

So, you’ll be dividing 20.6 ounces by 8 and get 2.6 ounces of milk. This is the amount of breast milk that you should be giving each feeding, which comes to eight times a day and a total of 20.6 ounces of milk. 

Your 8.4 pounds baby will need 2.6 (approx. 77 ml) ounces of breast milk in a bottle each feeding for a total of eight times a day. 

Amount of formula for 4 oz of breast milk

Now that we know how to arrive at the right amount of milk your baby needs each feeding depending on their weight, it’s only fitting to know how many scoops of formula you need to arrive at the perfect milk quantity for your baby’s every feeding.

You might be transitioning or weaning, where you’re now shifting to formula. Or there might be chances that you don’t have breastmilk around you as a parent and have to rely on formula for your baby.

Like every parent, you want your baby to be fed the correct amount. Taking the above example, if your baby weighs 8.4 pounds (3.34 kg), then you need 2.6 ounces of milk for one feed. 

Now, 4 oz of breast milk can be made from the formula by adding 2 scoops with 4 ounces of water. So, taking the above example as a reference to your baby, you should take 3 scoops and prepare enough for two feeds and 6 oz of formula milk. So, you can give 2.6 in each feeding and add the little remaining to the third bottle of feed.

Remember never to add extra water and follow the manufacturer’s instructions for formula making. Adding extra water will ruing the formula and lower down its nutritional value. 

Formula you wantOunces of waterScoops of formula
2 oz2 ounces1 scoop
4 oz4 ounces2 scoops
6 oz6 ounces3 scoops

One little reminder that formula can’t be made in odd numbers but even numbers as the ratio gets disturbed if you add half of the formula. You might ruin the mixture, which can either turn the formula into a concentrated one or too fluidic. 

Amount of formula needed for baby


When you first start feeding your newborn, your body is getting accustomed to producing milk, and so for the first couple of days, you might struggle to get enough breastmilk. Although feeding breastmilk is the best option if you can’t provide your little one with breastmilk, getting them the best formula you can work too.

As a newborn, they will demand milk every 2-3 hours and drink 1-2 ounces of milk per feeding. When they grow to be two weeks old, they will get hungry for 2-3 ounces of milk.

1-3 months of age

During this time, your baby’s appetite grows significantly, and so does their growth and mental development. They’ll let you know if they’re hungry, but you should keep a record of how many ounces of milk you’re feeding them and how frequently. 

A 2-month-old baby will require 4-5 ounces of milk every 3-4 hours. 

4-6 months of age

Around this time, many parents start experimenting with semi-solid foods, so your munchkin doesn’t need milk to survive, so their milk diet might reduce. Again depending on the baby to baby and not all babies might enjoy the idea of eating and still stick to drinking milk only.

At 4 months of age, your baby will need 4-6 ounces of milk per feeding and shift to 8 ounces of milk every 4-5 hours when they turn 6 months old. 

6-9 months of age

By this time, your baby must have included some food in their diet, so their milk needs might differ. But one thing is sure that you shouldn’t give them more than 32 ounces of milk per day and make sure their hunger needs are met by food.

They should be getting 4-8 ounces of milk per feeding.

9-12 months of age

Every baby learns to depend on some sort of solid food by this time. So their needs are now divided equally and met by both food and milk. Your baby will experiment with different foods during this time, and you should let them. 

Your baby around this time will need 7-8 ounces of milk per feeding.

After 12 months of age

Turning one year old is one of the most significant milestones in your and your baby’s life. By this time, they would still be experimenting with different solid food, but their milk needs will not be limited to cups or mugs. Giving your child 3 mugs of milk in a day is sufficient, and you can pair food with them, so it’s easier for your baby to transition to three meals in a day. 

Feeding breastmilk and formula at the same time

A young mom is bottle feeding her infant daughter a mixture of breastmilk and formula

Some parents choose to give both formula and breastmilk to their babies and sort of combine both into their baby’s diet. Some parents cannot produce the necessary amount of breastmilk, so they decide to combine it with formula. Sometimes, there’re just other medical conditions that make you compromise with a situation like this.

But combing formula and breastmilk isn’t a bad option at all. In fact, it’s a great way to introduce formula to your baby and give them the best of both options. Some parents tend to switch to formula entirely, which is good too.

Many parents think that feeding formula would take away the motherly experience from their baby, which includes not having enough skin contact. But, it ultimately depends on you and how to choose to handle the situation. Even with the formula, you can have skin contact, hold your baby in a breastfeeding position, and feed them milk. 

One thing that you should avoid, though, is mixing your breastmilk with formula and then giving it to your baby. The formula is always made with the manufacturer’s directions and not mixed in the breastmilk. Feed the breastmilk before then you can feed formula. 


Do babies need less formula than breast milk?

Just because you decided to feed your baby formula milk doesn’t mean you need to compensate for it by giving them more of it. While breastmilk will always be superior, formula is also a great option. Try to choose an iron-fortified formula.

You can decide how much formula to feed your baby by calculating the exact amount depending on their weight and age. Overfeeding can result in overweight which should be avoided. 

Can I breastfeed during the day and bottle feed at night?

Breastfeeding for the first 6 months of life is vital but not compulsory. So if you decide to bottle feed at night and breastfeed during the day, then that’s your personal choice. There’s no harm in adopting this lifestyle for your family.

This way, breastfeeding mothers can rest during the night, and their partner and other family members can be involved and responsible in feeding the baby. 

Can I mix breast milk from two different days?

Mixing two different times of breast milk together is not an issue as breast milk doesn’t go bad easily. Only when you can smell it go sour should you discard it. 

If your milk production is in lesser quantity one time, you can also feed formula to your baby. Just don’t mix breastmilk with formula. Feed breastmilk first, then give them formula as mixing them both can ruin the consistency of the formula. 

Don’t mix warm and refrigerated breastmilk. Only after you’ve warmed the breastmilk in a bottle in warm water should you combine it with other warm milk. 

Do formula-fed babies sleep better?

Some studies show that a formula-fed baby can sleep better and longer during the night than a breastfed baby. But the evidence is strong in older babies and not newborns or infants. Breastfed babies might face an issue and wake up more at night because breastmilk production might be lesser. 

Do you feed the same amount of formula as breastmilk?

It’s not of any use to compare formula with breastmilk, and both have different nutritional values, and of course, breastmilk is the preferred choice for most parents. But somehow, we can calculate how much formula to make, which can be equivalent to breastmilk per feeding based on your baby’s weight. 

You should make sure that your baby is not fed more than 32 ounces of milk in a day as it can result in overfeeding

To summarize

There could be multiple reasons why you can’t feed your baby breastmilk, which leaves you with the formula to compensate for their dietary needs. A formula is also a good option, but finding a suitable one for your baby can sometimes be tricky.

Once you’re done finding a suitable formula for your little munchkin, it all comes down to finding out the amount of milk you should be giving them each feeding based on their age and weight. From the above calculations, you can come to an easy conclusion for your baby. But usually, 4 oz of breastmilk can be made by using 2 scoops of formula with 4 ounces of water.

You should keep track of how much formula you’re feeding your little one as it can easily lead to overfeeding, which results in other issues. Have a happy feeding!

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As a writer for 1happykiddo, Saumya wants to help new parents and older siblings help raise the newest member added to the family. Her parenting tips come from her experience of being 15 years older than her youngest sibling. When not writing, you can find her reading novels, traveling, and cooking nutritious meals.

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