How many calories are in walnuts?
Walnuts has 183 calories per 1 oz (28 g, ~14 halves) — that's 654 calories per 100 g, roughly 9% of a 2,000-calorie day. Most of those calories come from fat.
USDA FoodData Central · english, raw · FDC 170187
Calories by portion
| Portion | Calories | Protein | Carbs | Fat |
|---|---|---|---|---|
| 1 oz (28 g, ~14 halves) | 183 | 4.3 g | 3.8 g | 18.3 g |
| 100 g | 654 | 15.2 g | 13.7 g | 65.2 g |
| 1 oz (28 g) | 185 | 4.3 g | 3.9 g | 18.5 g |
Where the calories come from
Protein 9% Carbs 8% Fat 84%
Calories computed from USDA per-100 g data (FDC 170187, SR Legacy). english, raw. The macro split uses general Atwater factors (protein and carbs ≈ 4 cal/g, fat ≈ 9 cal/g) and is approximate.
Walnuts are nutritious and genuinely filling — and they are the most calorie-dense of the common nuts, which is the number people miss. A standard 1 oz handful (28 g, about 14 halves) carries roughly 183 calories, and 100 g comes in at a hefty 654 calories — more than almonds (579) or peanuts (587). A small handful is only about 9% of a 2,000-calorie day, but it’s small enough to grab on autopilot, and that’s exactly where the calories sneak up. The reason walnuts top the nut bowl on calories sits in the macro split.
Where the calories come from
Almost everything here is fat — more of it than in any other common nut. Walnuts carry about 65 g of fat per 100 g (versus roughly 50 g for almonds and peanuts), and fat costs 9 calories a gram against 4 for protein and carbs. Run them through the standard Atwater factors and roughly 90% of the calories are fat, with protein and carbohydrate splitting the small remainder. More fat per gram simply means more calories per gram, which is the whole reason walnuts edge out the field at 654 per 100 g. None of that makes the fat bad — an unusually large share is plant-based omega-3 (ALA), the heart-healthy kind that’s genuinely hard to get from food — but healthy fat is still dense fat.
Why portion control is the whole game
The discipline walnuts demand is portion control, not avoidance. A measured 1 oz handful is about 183 calories of genuinely good nutrition; the trouble starts when “a handful” quietly becomes three. Eat from the bag and you can clear 400–500 calories without registering a single one — the same density that makes a small serving satisfying makes a large one a calorie trap, and walnuts being the densest nut means that trap is a touch deeper than with peanuts (~164 per ounce) or almonds. The reliable move is to measure once: about 14 halves is the right portion, and tipping them into a bowl rather than grazing from the package keeps walnuts working as the smart, omega-3-rich snack they are.
For the protein side of the picture — and why that per-100g protein number doesn’t make walnuts a protein source — see protein in walnuts.
Packaged nuts options, graded
Prefer something off the shelf? Here are the best-graded nuts in our catalog — each scored on our transparent Labelgrade. Check the calorie line on each label for your goal.
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Labelgrade 85/100 · 160 cal · 6 g protein
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Labelgrade 79/100 · 170 cal · 6 g protein
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Frequently Asked Questions
How many calories are in a 1 oz serving of walnuts?
About 183 calories in a 1 oz handful (28 g, roughly 14 halves), based on 654 calories per 100 g (USDA FDC 170187). That's the most calorie-dense of the common nuts, packed into a portion small enough to grab without thinking — which is the catch.
How many calories are in walnuts per 100 g or per ounce?
654 calories per 100 g, which works out to about 183 calories per ounce (28 g). Be careful with the per-100g figure: 100 g of walnuts is about 3.5 ounces and far more than a normal snack, so anchor on the ~183-calorie ounce for the realistic number.
Why are walnuts the most calorie-dense nut?
Because they're the fattiest. Walnuts carry about 65 g of fat per 100 g — more than almonds (~50 g) or peanuts (~50 g) — and fat has 9 calories a gram versus 4 for protein and carbs. More fat per gram means more calories per gram, which is why walnuts top the common nuts at 654 calories per 100 g (USDA FDC 170187).
Where do the calories in walnuts come from?
Overwhelmingly fat. By the standard Atwater factors, roughly 90% of walnuts' calories come from their ~65 g of fat per 100 g, with protein and carbohydrate splitting the small remainder. The good news is that much of that fat is plant-based omega-3 (ALA) — healthy, but still calorie-dense.
Why are walnuts so easy to overeat?
Because they're the densest common nut and effortless to graze on. A measured 1 oz handful is about 183 calories, but doubling it without noticing pushes you past 360 — a meal's worth of calories from a snack. The fix is to portion about 14 halves into a bowl instead of eating from the bag.
When was this data last verified?
2026-06-18, against USDA FoodData Central FDC 170187 (Nuts, walnuts, english; SR Legacy). We re-verify reference pages periodically and update when USDA revises its data.
Whole-food values are USDA reference data, not a Labelgrade (that score is for branded packaged products). See our methodology and the TDEE calculator to turn this into a daily target.