How Many Calories Does Breastfeeding Burn?

The average lactating woman (who is breastfeeding a newborn) produces between 25 and 32 ounces of milk every 24 hours; this results in a 325 – 500 calorie deficit. Calculations are shown below.

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  1. Exclusive Pumping
  2. Exclusive Breastfeeding

Our Breastfeeding Calorie Calculator

Breastfeeding Calorie Calculator
Ounces of Milk:
Age of child:

How Many Calories Breastfeeding Burns

The exact amount of energy used daily for lactation is still a matter of debate.

These calculations should only be used as a guideline; if you find that they are not working for you, you can tweak them until they do. Not everyone is the same, we are all unique, and therefore our bodies react differently.

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Do You Need to Consume More Calories for Breastfeeding?

The average lactating woman produces between 25 and 32 ounces of milk every 24 hours; this results in a 325 – 500 caloric deficit. Calculations are shown below.

It is also important to remember that the additional calories needed should come from nutritionally dense foods that contain protein, healthy fats, and vegetables if you are trying to lose weight and stay healthy. The quality of the foods consumed is more important than the quantity.

Once your extra calories are calculated, you should use an app such as Sparkpeople to determine your daily caloric allowance.

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Energy Used Depends On

  • Is your baby breastfed exclusively? Are any other supplements given?
  • The age of the child.

These calculations are only accurate if your baby is breastfeeding exclusively. The average metabolic rate would be different if you supplemented with formula or donor breast milk. Therefore, it cannot be calculated after six months since most babies start solids then.

How Our Breastfeeding Calorie Calculator Works.

For Exclusive Pumpers

How many calories does pumping burn?

This amount is more easily calculated for mothers who are pumping exclusively. You would take the amount of milk pumped in ounces and multiply it by 20 because there are 20 calories in every ounce of breast milk. For example: if you produce 40 ounces of milk per day, the milk's calories would equal 800 calories. (40 * 20 = 800)

You would also need to consider the energy needed to produce that milk (calories burned from breastfeeding). Production efficiency is 80%, therefore, this would be your calculation: 40 * 20 = 800 / 0.8 = 1000. That’s a total of 1000 calories needed per day to produce 40 ounces of milk.

But, your metabolism is tweaked during nursing to help you use your calories more efficiently, so you need fewer calories.

Once you have this amount, we need to subtract the postpartum basal metabolism (you get more out of your calories when breastfeeding). The following are average amounts.

  • 0 – 4 months = 300 cal
  • 4 months = 400 cal
  • Six months and onwards = 500 cal

So, for example, an exclusively pumping mother with a 3-month-old baby who expresses a total of 30 ounces per day:

30 * 20 / 0.8 = 750 – 300 (basal metabolism) = 450

Therefore, this mother would add an additional 450 cal to her expended calories for the day when working out how many calories she burns altogether.

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How Many Calories Breastfeeding Mothers Burn When Exclusive Breastfeeding

Weigh your baby before and after every feeding over a full 24-hour period. Subtract the before weight from the after-feeding weight to determine how much milk your baby has taken in during each feeding. At the end of the 24 hours, add up all the amounts to determine the volume taken in during 24 hours. Use the same calculation above. For example: if your newborn baby drinks a total of 30 ounces daily: 30 * 20 / 0.8 = 750 cal – 300 = 450

OR a few additional examples:

If your 4-month-old baby drinks 30 ounces per day:

30 (ounces of milk) * 20 (calories in milk) / 0.8 (energy to make milk) – 400 (metabolic increased rate for mother with 4-month-old) = 350 (the extra needed calories for breastfeeding)

If your 8-month-old baby drinks 32 ounces per day:

32 * 20 / 0.8 – 500 = 300


The number of calories you consume will also depend on your

1. Activity level

2. Current weight

3. Nutritional status

Most lactating women will be a little more peckish than usual; you must listen to your body.

Work out an Average Amount

You can use an average amount if you do not want to pump or weigh your baby to determine the exact amount of milk produced. Calculate your average amount of milk produced by converting the appropriate amount below from ml to Fluid ounces. Use this in the above calculator to calculate your average amount of extra calories needed. The only snag in calculating an average amount would be if your baby were going through a growth spurt, in which case they would drink more milk than usual.

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Always check with your doctor before changing your diet, especially when on any medications.