How much protein is in walnuts?

Walnuts has 15.2 g of protein per 100 g and 4.3 g per 1 oz (14 halves) (28 g). That is 2.3 g of protein per 100 kcal — essentially not a protein source.

Where do these calorie figures come from?

USDA FoodData Central record 170187, “Nuts, walnuts, english” (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

Nuts and peanut butterUSDA SR LegacyFDC 170187

Calories in walnuts

USDA FoodData Central record for “Nuts, walnuts, english” — per 100 g, per every USDA serving size, and next to the other nuts and peanut butter rows.

The short answer

Walnuts: 654 kcal per 100 g. 1 oz (14 halves) (28 g) is 186 kcal with 4.3 g of protein. Source: USDA FoodData Central record 170187, "Nuts, walnuts, english".

Per 100 g

Nutrient	Per 100 g	Share of energy
Energy	654 kcal	100%
Protein	15.2 g	9%
Fat	65.2 g	84%
Carbohydrate	13.7 g	8%

Walnuts is 654 kcal per 100 g in USDA FoodData Central (SR Legacy). Of that energy, about 9% comes from protein, 84% from fat and 8% from carbohydrate. That works out to 2.3 g of protein per 100 kcal — essentially not a protein source.

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	654	15.2 g	65.2 g	13.7 g
1 cup, chopped	117 g	765	17.8 g	76.3 g	16 g
1 cup, ground	80 g	523	12.2 g	52.2 g	11 g
1 cup, in shell, edible yield (7 nuts)	28 g	183	4.3 g	18.3 g	3.8 g
1 cup shelled (50 halves)	100 g	654	15.2 g	65.2 g	13.7 g
1 cup pieces or chips	120 g	785	18.2 g	78.2 g	16.4 g
1 oz (14 halves)	28 g	186	4.3 g	18.5 g	3.9 g

Compared with other nuts and peanut butter

Food	kcal / 100 g	Protein / 100 g	Per serving
Almonds	579	21.2 g	164 kcal · 1 oz (23 whole kernels)
Walnuts	654	15.2 g	186 kcal · 1 oz (14 halves)
Cashews	553	18.2 g	157 kcal · 1 oz
Pistachios	560	20.2 g	159 kcal · 1 oz (49 kernels)
Peanuts	567	25.8 g	161 kcal · 1 oz
Peanut butter	598	22.2 g	191 kcal · 2 tbsp
Unsalted peanut butter	598	22.2 g	191 kcal · 2 tbsp

Other tables in nut and seed products

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

Calories in chia seeds486 kcal / 100 g

Questions about walnuts

How many calories are in walnuts?: Walnuts: 654 kcal per 100 g. 1 oz (14 halves) (28 g) is 186 kcal with 4.3 g of protein. Source: USDA FoodData Central record 170187, "Nuts, walnuts, english".
How much protein is in walnuts?: Walnuts has 15.2 g of protein per 100 g and 4.3 g per 1 oz (14 halves) (28 g). That is 2.3 g of protein per 100 kcal — essentially not a protein source.
Where do these calorie figures come from?: USDA FoodData Central record 170187, “Nuts, walnuts, english” (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 “walnuts” into calorie.one and the app matches this exact record — “Nuts, walnuts, english” — 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 Calories in olive oil, butter and cooking fats.