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Calories in Walnuts

Q: How many calories in walnuts?

Walnuts have 654 calories per 100g. One oz (14 halves, 28g): 185 kcal.

Updated July 2026 · Source: USDA FoodData Central

654

kcal

per 100g

15.2

Protein

65.2

Fat

13.7

Carbs

6.7

Fiber

185

kcal per 1oz / 14 halves (28g)

654

kcal per 100g

185

kcal per oz (28g)

🐟Richest nut ALA omega-3 — 2.57g per oz

🧠Associated with improved cognitive function

😴Melatonin content supports sleep

💊Vitamin B6 — 32% DV per 100g

🌿6.7g fiber per 100g

❤️Reduces CRP inflammation marker

🥜 Calculate Calories for Any Walnuts Weight

Weight28g

Nutrition Facts

Per 100g walnuts

* % Daily Value based on a 2,000 kcal diet.

Quick summary: Walnuts contain 654 calories per 100g — 185 kcal per oz. The richest nut source of ALA omega-3 (2.57g per oz). The only nut with significant omega-3. Regular consumption is associated with reduced inflammation, improved cognitive function, and better sleep (melatonin content).

Vitamins & Minerals — per 100g

Nutrient	Amount	% Daily Value
Copper	1.59mg	177%
Manganese	3.41mg	148%
Magnesium	158mg	38%
Vitamin B6	0.54mg	32%
Phosphorus	346mg	28%
Folate	98µg	25%
Zinc	3.09mg	28%
Iron	2.91mg	16%
Potassium	441mg	9%
Thiamine	0.34mg	28%

Calories in Walnuts by Weight

Weight	Calories	Fat	Protein	Net Carbs

Macronutrient Breakdown — per 100g

Fat65.2g · 85% of calories

Protein15.2g · 9% of calories

Carbs13.7g · 4% of calories

Fiber6.7g (in carbs)

Net carbs: 7.0g/100g. 65.2g fat — highest fat nut. 47% polyunsaturated — richest nut ALA omega-3 (9.08g/100g). Contain melatonin — one of few foods with direct melatonin.

Micronutrient Highlights

🐟

ALA Omega-3

9.08g

Fatty acid

Richest nut source — 2.57g per oz

🧠

Copper

1.59mg

177% DV

Iron metabolism and antioxidant defence

⚡

Manganese

3.41mg

148% DV

Antioxidant enzymes — highest of any nut

⚡

Magnesium

158mg

38% DV

ATP, muscle, nerve

💊

Vitamin B6

0.54mg

32% DV

Serotonin, dopamine synthesis

🌿

Fiber

6.7g

24% DV

Gut health and satiety

Walnut Health Benefits

Richest Nut Omega-3 Source

The only commonly available nut with significant omega-3. One oz provides 2.57g ALA. Multiple RCTs show walnut consumption reduces triglycerides, lowers blood pressure, and reduces inflammation. The Mediterranean diet's walnut component contributes to its 30% reduction in cardiovascular events.

Brain Health — Cognitive Protection

The WAHA trial found daily walnuts significantly improved cognitive performance in older adults — memory, processing speed, and executive function. Walnuts contain ALA (DHA precursor), B6 (neurotransmitter synthesis), folate, and polyphenols that cross the blood-brain barrier. A 2020 Nutrients study found higher walnut consumption associated with 26% lower odds of depression in older adults.

Ellagitannins — Gut Antioxidants

Walnuts are the richest nut source of ellagitannins — polyphenols gut bacteria convert to urolithins with powerful anti-inflammatory and anti-cancer effects. ~40% of people have gut microbiomes capable of efficient conversion, for whom walnuts provide particularly potent antioxidant benefits.

Melatonin for Sleep

Walnuts contain melatonin — one of the few foods with direct melatonin content. Studies show walnut consumption increases blood melatonin. Combined with tryptophan and magnesium, walnuts may support sleep quality.