Calories in Oatmeal: Protein, Carbs and Fat per 100 g and per Serving
Quick answer: A cup of oatmeal cooked with water (234 g) has about 165 kcal: 28 g of carbohydrate, 5.9 g of protein, 3.6 g of fat and 4.0 g of fiber. Dry oats are 379 kcal per 100 g, cooked oatmeal 71 kcal per 100 g. Both numbers are right. They describe the same oats before and after they soak up water, and mixing them up is the most common way oatmeal gets logged wrong.
Calories by serving
Rolled and quick oats share one USDA record, so these numbers work for both. The first two rows are dry oats, measured before cooking. The last two are oatmeal cooked with water and no salt.
| Serving | Weight | Calories | Protein | Carbs | Fat | Fiber |
|---|---|---|---|---|---|---|
| ⅓ cup dry oats | 27 g | 100 kcal | 3.6 g | 18 g | 1.8 g | 2.7 g |
| 1 cup dry oats | 81 g | 305 kcal | 11 g | 55 g | 5.3 g | 8.2 g |
| ¾ cup cooked oatmeal | 175 g | 125 kcal | 4.4 g | 21 g | 2.7 g | 3.0 g |
| 1 cup cooked oatmeal | 234 g | 165 kcal | 5.9 g | 28 g | 3.6 g | 4.0 g |
Sugar is under 1 g in every row: plain oats have almost none. Every gram of sugar in a bowl of oatmeal comes from what you add to it.
A cup of cooked oatmeal holds about 44 g of dry oats. The rest is water. That's why a level cup of dry oats, 305 kcal, makes almost two bowls.
Per 100 g nutrition
| Nutrient | Dry oats | Cooked with water |
|---|---|---|
| Calories | 379 kcal | 71 kcal |
| Protein | 13 g | 2.5 g |
| Fat | 6.5 g | 1.5 g |
| Carbohydrate | 68 g | 12 g |
| Fiber | 10 g | 1.7 g |
| Sugars | 1.0 g | 0.3 g |
| Water | 11 g | 84 g |
| Iron | 4.3 mg | 0.90 mg |
| Magnesium | 140 mg | 27 mg |
| Potassium | 360 mg | 70 mg |
Dry oats have 5.3 times the calories of cooked oatmeal, gram for gram. If you weigh your oats, weigh them dry and log them as dry. A 40 g scoop of dry oats is about 150 kcal however much water you cook it in.
Forms and variants
Per 100 g:
| Form | Calories | Protein | Fat | Carbs | Fiber | FDC ID |
|---|---|---|---|---|---|---|
| Oats, regular and quick, dry | 379 kcal | 13 g | 6.5 g | 68 g | 10 g | 173904 |
| Oatmeal, regular and quick, cooked with water, no salt | 71 kcal | 2.5 g | 1.5 g | 12 g | 1.7 g | 173905 |
| Instant oatmeal, plain, fortified, prepared with water | 68 kcal | 2.4 g | 1.4 g | 12 g | 1.7 g | 171662 |
Plain instant oatmeal comes out almost the same as rolled oats: a cooked cup (234 g) is about 160 kcal. The difference is in the extras. The fortified instant record has 6.0 mg of iron and 80 mg of calcium per 100 g of cooked oatmeal, against 0.90 mg and 9 mg for regular oats. It also has 49 mg of sodium per 100 g instead of 4. Flavored instant packets (maple and brown sugar, apple cinnamon) add sugar that varies by brand, so use the label for those.
Steel-cut oats are whole oat kernels cut into pieces rather than rolled flat. SR Legacy has no separate record for them, so use the dry serving in grams from the bag.
What goes in the bowl
The oats are rarely the biggest number. Here is what common additions bring:
| Addition | Amount | Calories |
|---|---|---|
| Whole milk instead of water | ½ cup (122 g) | 74 kcal |
| Honey | 1 tbsp (21 g) | 64 kcal |
| Brown sugar | 1 tsp (3 g) | 11 kcal |
| Peanut butter | 2 tbsp (32 g) | 190 kcal |
| Medium banana, sliced | 118 g | 105 kcal |
A cup of oatmeal with ½ cup of whole milk, a tablespoon of honey and a sliced banana comes to about 410 kcal and 11 g of protein. Stir in two tablespoons of peanut butter and it's about 600 kcal. That's still a fine breakfast. It's just a different number from 165, and the app needs to know which one you ate. Numbers for the banana are in calories in banana.
Oatmeal and weight loss
A cup of plain cooked oatmeal is 165 kcal and 84% water. It has 4.0 g of fiber, about 14% of the 28 g Daily Value on US food labels. That's a big, warm bowl for the calories.
Protein is the weak spot: 5.9 g per cup. Cooking the oats in milk, adding Greek yogurt or eating eggs on the side turns the bowl into a more complete breakfast. See how much protein per day for a target. If you are eating in a deficit, the toppings are where to look first: honey, syrup and nut butter can triple a bowl without making it look much bigger. Start with how to set a calorie deficit.
How to log it
Voice handles the wording that matters: "a cup of cooked oatmeal with half a cup of whole milk and a tablespoon of honey." Say whether the amount is cooked or dry. "Half a cup of oats" can mean about 155 kcal dry or about 83 kcal cooked.
Photo sees the bowl, the banana slices and the berries. It can't see milk stirred in, a spoon of sugar that has dissolved, or nut butter under the surface. Add those by voice or text.
Barcode works for instant packets and for the oat canister, where the serving is usually given dry.
CalMePlease logs a bowl of oatmeal from a voice note or a photo, splits it into oats and each topping, and shows the estimated grams so you can correct them in one tap. More on voice food logging.
FAQ
How many calories are in a cup of oatmeal? About 165 kcal for a cup of oatmeal cooked with water (234 g). A cup of dry oats (81 g) is about 305 kcal and cooks into nearly two such bowls.
How many calories are in 100 g of oats? 379 kcal per 100 g of dry rolled or quick oats, and 71 kcal per 100 g of oatmeal cooked with water.
How much protein is in oatmeal? 5.9 g in a cup of cooked oatmeal and 13 g per 100 g of dry oats. Cooking in milk adds about 3.8 g per half cup.
Is instant oatmeal the same as rolled oats? Plain instant is close: about 160 kcal per cooked cup against 165. Flavored packets add sugar, so check the label.
Should I weigh oats dry or cooked? Dry. The dry weight doesn't change, while cooked weight depends on how much water you used and how long it cooked.
Is oatmeal good for weight loss? Plain oatmeal is filling for its calories: 165 kcal and 4 g of fiber per cup. It helps a deficit when the toppings stay modest.
Data: USDA FoodData Central, SR Legacy — Cereals, oats, regular and quick, not fortified, dry (FDC ID 173904); Cereals, oats, regular and quick, unenriched, cooked with water, without salt (FDC ID 173905); Cereals, oats, instant, fortified, plain, prepared with water (FDC ID 171662); Honey (FDC ID 169640); Milk, whole, 3.25% milkfat (NDB 01077); Peanut butter, smooth style, with salt (NDB 16098); Sugars, brown (NDB 19334). Fiber Daily Value: FDA Nutrition Facts label (28 g). Values checked October 2026.
Related: Calories in banana · How much fiber per day · Calories in Greek yogurt
CalMePlease logs a bowl of oatmeal from a voice note or a photo, with each topping as its own line. Free on the App Store.
