How Many Calories in Oats? Nutrition Facts & Macros
A serving of dry oats (40 g) has 152 calories
Protein 5.3g · Carbs 27.1g · Fat 2.6g
Dry oats are a whole grain powerhouse — 13.15 g of protein and 10.1 g of fiber per 100 g, with outstanding beta-glucan (a soluble fiber proven to lower cholesterol). When cooked with water, 40 g of dry oats becomes roughly one bowl (240 g) at about 152 kcal. Good magnesium content (138 mg per 100 g) supports muscle function and energy metabolism. Here is everything you need to know about oat calories and macros, based on USDA data. Dry oats contain only about 11% water.
1586 kJ · per 100g · Water: 10.84 g
Calorie Calculator: Oats (Dry)
40 g Oats (Dry) contains 152 kcal
Calories by Portion Size
| Portion | Calories | Protein | Carbs | Fat |
|---|---|---|---|---|
| 1 serving dry (40 g) | 152 kcal | 5.3g | 27.1g | 2.6g |
| 1/2 cup dry (40 g) | 152 kcal | 5.3g | 27.1g | 2.6g |
| 100 grams | 379 kcal | 13.2g | 67.7g | 6.5g |
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Oats (Dry) — Nutrition Facts
| Oats (Dry) | per 100g |
|---|---|
| Calories | 379 kcal |
| Protein | 13.15 g |
| Fat | 6.52 g |
| Carbs | 67.7 g |
| Fiber | 10.1 g |
| Sugar | 0.99 g |
| Sodium | 6 mg |
| Potassium | 362 mg |
| Magnesium | 138 mg |
| Phosphorus | 410 mg |
| Vitamin C | 0 mg |
| Vitamin B6 | 0.1 mg |
| Folate | 32 mcg |
| Manganese | 3.63 mg |
| Water | 10.84 g |
Source: USDA FoodData Central (FDC ID: 173904) · Data verified April 2026
Variations
Rolled oats (regular)
379 kcal per 100 g. The standard variety — steamed and flattened whole oat groats. Cook in about 5 minutes on the stove. Most common form in stores and recipes. Good balance of texture and cooking speed. This is the USDA reference form (FDC 173904).
Steel-cut oats (Irish oats)
Approximately 379 kcal per 100 g — same nutrition as rolled oats since it is the same grain, just cut differently. Whole oat groats chopped into pieces with steel blades instead of being rolled flat. Chewier texture and nuttier flavor. Takes 20–30 minutes to cook on the stove. Lower glycemic index than rolled oats due to less processing. Popular for overnight slow-cooker recipes.
Instant oats
Approximately 375 kcal per 100 g. Pre-cooked, dried, and rolled thinner than regular oats for faster preparation — just add hot water or microwave for 1–2 minutes. Nutritionally almost identical to rolled oats when unflavored. The thinner flakes create a softer, creamier texture. Flavored instant packets often contain 10–15 g of added sugar per serving. For tracking, always use plain unflavored instant oats and add your own toppings.
Dietary Perspectives
For Weight Loss
Outstanding for weight loss despite 379 kcal per 100 g dry. A 40 g dry serving has only 152 kcal but cooks into a large, filling bowl with 5.3 g of protein, 4 g of fiber, and massive volume from water absorption. Beta-glucan fiber forms a gel in the stomach that slows gastric emptying and keeps you full for hours. Studies consistently show oatmeal is one of the most satiating breakfast foods. Add berries and a scoop of protein powder for a sub-300 kcal breakfast that lasts until lunch.
For Athletic Performance
Excellent slow-release carbs — a 40 g dry serving provides about 27 g of carbs for sustained energy. Good magnesium content (138 mg per 100 g) supports muscle function and recovery. At 13.15 g of protein per 100 g dry, oats are high-protein for a grain — combine with milk or yogurt for a complete pre-workout meal. Popular choice 2–3 hours before training. Overnight oats are convenient for early morning sessions. The beta-glucan fiber supports cardiovascular health, beneficial for endurance athletes.
For Keto
NOT suitable for keto — 57.6 g net carbs per 100 g (67.7 g total carbs minus 10.1 g fiber). Even a small 40 g serving has about 23 g net carbs, exceeding strict keto limits in one sitting. Oats are a whole grain, meaning concentrated starch despite the healthy fiber content. For a keto 'oatmeal' texture, try hemp hearts + chia seeds + flaxmeal cooked with cream — about 3 g net carbs per serving with a similar warm, creamy consistency.
Frequently Asked Questions
How many calories are in oats?
Dry oats contain 379 calories per 100 g. A standard serving (40 g) has about 152 calories — but when cooked with water, this 40 g becomes a full bowl (~240 g) at the same 152 kcal. The difference between dry and cooked oats is simply water: dry = 379 kcal/100 g, cooked = 71 kcal/100 g. Always check whether your nutrition label shows dry or cooked values.
How much protein is in oats?
Dry oats have 13.15 g of protein per 100 g — unusually high for a grain. A 40 g serving provides 5.3 g of protein, roughly equivalent to one small egg. Combined with dairy (milk, yogurt) or a scoop of protein powder, an oat-based breakfast can easily reach 20-30 g of protein. Oat protein is not complete (low in lysine), so pairing with dairy or legumes improves amino acid balance.
Are oats healthy?
Oats are one of the healthiest grains available. They are rich in beta-glucan (a soluble fiber clinically proven to lower LDL cholesterol by 5-10%), have 10.1 g of total fiber per 100 g, and provide 138 mg of magnesium (33% DV). They also contain manganese (3.63 mg, 158% DV) and phosphorus (410 mg). The main consideration is portion control — dry oats are calorie-dense at 379 kcal per 100 g, so weighing your portion matters.
Oats vs cereal — which is healthier?
Oats are significantly healthier than most breakfast cereals. Dry oats have 10.1 g of fiber vs 0.7 g in corn flakes, 13.15 g of protein vs 5.88 g, and only 0.99 g of sugar vs 10.6 g in corn flakes. Most cereals are highly processed with added sugar and stripped of fiber. Oats are a whole grain with intact nutrients. The one advantage of some fortified cereals is added vitamins (B12, iron), which oats lack naturally.
Are oats good for weight loss?
Oats are outstanding for weight loss despite their calorie density (379 kcal dry). A 40 g dry serving has only 152 kcal but cooks into a large, filling bowl with 5.3 g of protein, 4 g of fiber, and massive volume from water absorption. Beta-glucan fiber forms a gel that slows digestion and keeps you full for hours. Studies consistently show oatmeal is one of the most satiating breakfast foods. Add berries and a scoop of protein for a sub-300 kcal breakfast that lasts until lunch.
Are oats keto-friendly?
No — oats are not suitable for a ketogenic diet. With 67.7 g of carbs and 10.1 g of fiber per 100 g, that is 57.6 g of net carbs — nearly three times the typical 20 g daily keto limit. Even a small 40 g serving has about 23 g of net carbs, which exceeds strict keto limits in one sitting. Oats are a whole grain, meaning concentrated starch. For a keto 'oatmeal' texture, try hemp hearts + chia seeds + flaxmeal cooked with cream — about 3 g net carbs per serving.
Compare with Similar Foods
| Portion | kcal | Protein | Carbs | Fat |
|---|---|---|---|---|
| Oats (Dry) | 379 | 13.15g | 67.7g | 6.52g |
| Oatmeal (Cooked) | 71 | 2.54g | 12g | 1.52g |
| Granola (Homemade) | 489 | 13.67g | 53.88g | 24.31g |
| Cereal (Corn Flakes) | 384 | 5.88g | 88g | 0.91g |
| Brown Rice (Cooked) | 123 | 2.74g | 25.58g | 0.97g |
per 100g
Per 100 g dry, oats have 379 kcal — similar to other dry grains like rice (360 kcal). But oats have far more protein (13.15 g vs 7.1 g in rice) and fiber (10.1 g vs 1.3 g). Compared to cooked oatmeal (71 kcal/100 g), dry oats look calorie-dense — but it is the same food, just without added water.
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