Calories in Walnuts: Per Ounce and Per Half
One ounce of raw walnuts (about 14 halves) provides 185 calories, 18 g of total fat, 4 g of protein, and 4 g of carbohydrate, according to USDA FoodData Central (FDC ID 170187).
Walnuts are one of the most calorie-dense whole foods you will encounter. That density is not a reason to avoid them, but it is a reason to measure them.
Calories and macros by serving size
| Serving | Weight | Calories | Fat | Protein | Carbs | Fiber |
|---|---|---|---|---|---|---|
| 1 walnut half | ~6 g | 39 kcal | 4 g | 1 g | under 1 g | 0.4 g |
| 1 oz / ~14 halves | 28 g | 185 kcal | 18 g | 4 g | 4 g | 2 g |
| 1/4 cup (chopped) | ~30 g | 196 kcal | 20 g | 5 g | 4 g | 2 g |
| 1/2 cup (halves) | ~58 g | 380 kcal | 38 g | 9 g | 8 g | 4 g |
| 100 g | 100 g | 654 kcal | 65 g | 15 g | 14 g | 7 g |
Source: USDA FoodData Central, raw English walnuts, FDC ID 170187.
Where the calories come from
Nearly all the energy in walnuts comes from fat — 65 g per 100 g of nut. The dominant fat is polyunsaturated, including roughly 13 g of alpha-linolenic acid (ALA, the plant omega-3) per ounce, which is unusually high for a whole food. Protein is moderate at about 15 g per 100 g. Net carbohydrates are low: roughly 7 g per 100 g once fiber is subtracted, which is why walnuts appear in many low-carb and ketogenic plans.
Fat carries 9 kcal per gram, so a mostly-fat food is always calorie-dense by volume. A quarter-cup of chopped walnuts on oatmeal or a salad adds close to 200 calories — invisible in volume but very real in the total.
To see how a daily walnut habit fits your energy budget, use the TDEE calculator to find your maintenance number, then factor in your other meals.
Does it fit your goals?
Weight loss. Walnuts can work in a calorie deficit, but only when portioned. The one-ounce serving is the right anchor: weigh it or count out 14 halves rather than eating from the container. Research consistently shows that hunger signals are suppressed longer after higher-fat, higher-fiber snacks, which means a measured portion of walnuts before lunch may reduce overall intake — but unmeasured eating easily erases that advantage.
Blood sugar management. Walnuts have a glycemic index near zero. Their 4 g of carbohydrate per ounce is mostly fiber, so they produce minimal post-meal glucose response. Clinical trials (Tapsell et al., Diabetes Care 2004) show walnuts do not worsen glycaemic control and may improve lipid markers in type 2 diabetes. If you are tracking carbohydrates for glucose management, you can calculate net carbs using the net-carbs calculator — walnuts come in at roughly 2 g net carbs per ounce.
Muscle gain / higher protein needs. With only 4 g of protein per ounce, walnuts are not a primary protein source. Pair them with Greek yogurt or cottage cheese rather than relying on them to meet your protein target. For a full picture of your daily protein goal, see our guide on protein targets for weight loss.
Practical portioning
The most common walnut mistake is eating by feel rather than by count or weight. A loose “handful” varies from 1 oz to 3 oz — that is 185 to 555 calories from the same gesture. Counting 14 halves takes under 10 seconds.
Photograph your walnut snack or the dish you added them to, and CalEye logs the portion and macros in seconds — no food scale required.
Frequently asked questions
- How many calories are in one walnut half?
- One walnut half (roughly 6 g) contains about 39 calories, 4 g of fat, and under 1 g of carbohydrate, based on USDA FoodData Central data for raw walnuts (FDC ID 170187).
- Are walnuts good for weight loss?
- Walnuts can fit a weight-loss diet when portioned carefully. At 185 calories per ounce, their high fat and fiber content increases satiety, which can reduce overall intake — but the calories add up quickly if you eat from the bag without measuring.
- Do walnuts raise blood sugar?
- Walnuts have a negligible glycemic impact. They contain less than 4 g of carbohydrate per ounce, almost all from fiber, so they produce very little blood-glucose response and are generally well tolerated by people managing type 2 diabetes or prediabetes.