How much protein is in skim milk?

Skim milk has 3.4 g of protein per 100 g and 8.3 g per 1 cup (245 g). That is 10 g of protein per 100 kcal — a solid protein-per-calorie ratio for a whole food.

Where do these calorie figures come from?

USDA FoodData Central record 171269, “Milk, nonfat, fluid, with added vitamin A and vitamin D (fat free or skim)” (SR Legacy, FDC SR Legacy 2018-04 + FNDDS 2024-10-31). Energy is USDA nutrient 1008 (Energy, kcal); protein, fat and carbohydrate are read from the same record. USDA data is in the public domain, and the FDC ID above links straight to it.

All foods

Milk and milk alternativesUSDA SR LegacyFDC 171269

Calories in skim milk

USDA FoodData Central record for “Milk, nonfat, fluid, with added vitamin A and vitamin D (fat free or skim)” — per 100 g, per every USDA serving size, and next to the other milk and milk alternatives rows.

The short answer

Skim milk: 34 kcal per 100 g. 1 cup (245 g) is 83 kcal with 8.3 g of protein. Source: USDA FoodData Central record 171269, "Milk, nonfat, fluid, with added vitamin A and vitamin D (fat free or skim)".

Per 100 g

Nutrient	Per 100 g	Share of energy
Energy	34 kcal	100%
Protein	3.4 g	39%
Fat	0.1 g	3%
Carbohydrate	5 g	58%

Skim milk is 34 kcal per 100 g in USDA FoodData Central (SR Legacy). Of that energy, about 39% comes from protein, 3% from fat and 58% from carbohydrate. That works out to 10 g of protein per 100 kcal — a solid protein-per-calorie ratio for a whole food.

Per serving

The serving sizes USDA lists for this record, priced from the per-100 g figures above. Nothing here is rounded to a “portion” — the gram weight next to each label is what the calories are computed from.

Serving	Weight	Calories	Protein	Fat	Carbs
100 g	100 g	34	3.4 g	0.1 g	5 g
1 cup	245 g	83	8.3 g	0.2 g	12.3 g
1 fl oz	31 g	10	1 g	0 g	1.5 g
1 quart	980 g	333	33.3 g	1 g	49 g

Compared with other milk and milk alternatives

Food	kcal / 100 g	Protein / 100 g	Per serving
Whole milk	61	3.2 g	149 kcal · 1 cup
2% milk	50	3.3 g	122 kcal · 1 cup
Skim milk	34	3.4 g	83 kcal · 1 cup
Chocolate milk (whole)	83	3.2 g	208 kcal · 1 cup
Unsweetened almond milk	15	0.4 g	39 kcal · 1 cup
Sweetened vanilla almond milk	38	0.4 g	91 kcal · 1 cup

Other tables in dairy and egg products

The same numbers for the foods this one usually shares a plate — or a shopping list — with.

Questions about skim milk

How many calories are in skim milk?: Skim milk: 34 kcal per 100 g. 1 cup (245 g) is 83 kcal with 8.3 g of protein. Source: USDA FoodData Central record 171269, "Milk, nonfat, fluid, with added vitamin A and vitamin D (fat free or skim)".
How much protein is in skim milk?: Skim milk has 3.4 g of protein per 100 g and 8.3 g per 1 cup (245 g). That is 10 g of protein per 100 kcal — a solid protein-per-calorie ratio for a whole food.
Where do these calorie figures come from?: USDA FoodData Central record 171269, “Milk, nonfat, fluid, with added vitamin A and vitamin D (fat free or skim)” (SR Legacy, FDC SR Legacy 2018-04 + FNDDS 2024-10-31). Energy is USDA nutrient 1008 (Energy, kcal); protein, fat and carbohydrate are read from the same record. USDA data is in the public domain, and the FDC ID above links straight to it.

How calorie.one logs it

Type “skim milk” into calorie.one and the app matches this exact record — “Milk, nonfat, fluid, with added vitamin A and vitamin D (fat free or skim)” — estimates the grams, and shows the line with its USDA label. You correct the amount; the per-100 g figure is never guessed. That split between recognition and arithmetic is the whole methodology. For the numbers in context, read How much protein do you need per day?.