Protein in Milk: Grams per Cup, Glass and 100 ml

The protein in milk is easy to remember: about 8 g per cup, whether it's whole, 2% or skim. Cow's milk has roughly 3.2 to 3.4 g of protein per 100 g, and the fat level barely affects it. What changes is the calorie count. This guide covers milk protein by serving and type, how plant milks compare, what kind of protein milk contains, and simple ways to use milk to raise the protein in your day.

Values below are from USDA FoodData Central SR Legacy entries for whole (3.25%), 2%, 1% and skim milk, and unsweetened soy milk.

Milk protein by type

Milk protein per cup and glass

Calories per cup are about 149 kcal for whole, 122 for 2%, 102 for 1% and 83 for skim. Milk weighs about 3% more than water, which is why 250 ml is about 258 g.

What kind of protein is in milk?

Milk protein is roughly 80% casein and 20% whey. Both are complete proteins with all nine essential amino acids:

That mix is why milk works well after exercise: whey gives a quick rise in amino acids, and casein keeps them coming. The ISSN position stand on protein and exercise lists dairy proteins among the high-quality options for supporting muscle protein synthesis. In a 12-week training study, young men who drank fat-free milk after lifting gained more lean mass than those who drank a soy drink or a carbohydrate drink with the same calories. It was a small study in novice lifters, so treat it as supportive rather than definitive.

Protein per calorie

If you're counting calories, skim gives nearly twice the protein per calorie of whole milk. If you're trying to gain weight or fuel long days, whole milk's extra energy is useful. Compare with other foods in the protein density calculator.

Cow's milk vs plant milks

Plant milk figures except soy are typical label values, not USDA entries, and vary a lot between brands. Soy and pea milk are the only common plant milks that match dairy on protein. If you've switched to oat or almond milk for your coffee and smoothies, you've lost most of the protein; see high-protein vegan meals for ways to make it up.

Ultra-filtered milk

Ultra-filtered milks are passed through fine filters that concentrate the protein and remove some lactose and sugar. Label values are often around 13 g of protein per 240 ml, about 50% more than regular milk, with less sugar. They're useful if you want more protein per glass, and usually cost more.

Chocolate milk

Reduced-fat chocolate milk has about 3 g of protein per 100 g, similar to plain milk, but more carbohydrate from added sugar (about 12 g per 100 g in the USDA entry). That carb-to-protein mix is why it's often suggested as a cheap recovery drink after long runs or hikes. Watch the sugar on rest days.

Using milk to add protein

1. Oats cooked in milk instead of water add about 8 g per cup of milk. See high-protein overnight oats.
2. Smoothies made with milk and Greek yogurt can reach 25 to 30 g without powder; see high-protein smoothie without protein powder.
3. Protein shakes mixed with milk instead of water add about 8 g and a creamier texture; see protein shake recipes.
4. Milk powder stirred into soups, mashed potato, porridge or baking adds protein without much volume. Skim milk powder is about a third protein by weight (check the label).
5. A glass with meals that are light on protein, like toast or pasta.

How much milk is reasonable?

Milk can be part of most diets. Two to three cups a day provides about 16 to 24 g of protein and a large share of daily calcium. Dietary guidance such as the Dietary Guidelines for Americans includes dairy or fortified soy alternatives as part of a healthy pattern, with lower-fat options often recommended.

Work out where milk fits in your total protein with the protein intake calculator.

Milk on the trail

Fresh milk doesn't keep on multi-day trips, but milk powder does, and it's one of the most useful backpacking ingredients:

• Whole milk powder adds calories and fat as well as protein.
• Add it to porridge, couscous, mashed potato flakes and hot chocolate.
• Mix it with granola in a bag so you only need to add water at camp.

See backpacking breakfast ideas and high-calorie backpacking food. Shelf-stable UHT cartons work for car camping.

Lactose intolerance

Milk contains about 5 g of lactose per 100 g. If milk upsets your stomach:

• Lactose-free milk has the same protein; the lactose is broken down by an added enzyme.
• Ultra-filtered milk is often lactose-free too.
• Hard cheese and Greek yogurt have much less lactose per gram of protein.
• Soy milk is lactose-free and matches dairy on protein.

Milk in a high-protein day

Here's how milk can fit into a day aimed at about 120 g of protein:

Milk supplies about a quarter of the total here, without any special products. See protein in cottage cheese for the evening option.

Is milk protein better than plant protein?

Per gram, dairy protein is highly digestible and rich in leucine. Soy protein is the closest plant match. For most people eating enough total protein from a variety of foods, the difference is small. What matters more is reaching your daily target.

Bottom line

Milk gives about 8 g of protein per cup regardless of fat level, with skim offering the most protein per calorie and whole milk the most energy. Soy and pea milk match it; oat and almond milk don't come close. A glass with a light meal, milk in your oats, or milk powder in camp food are easy ways to add protein.

Sources: USDA FoodData Central; ISSN position stand on protein and exercise; Hartman et al., milk after resistance exercise (2007); Dietary Guidelines for Americans.