Calories in an onion
An onion (1 medium, 110 g) has 44 calories, with 1.2 g of protein, 10.3 g of carbohydrates and 0.1 g of fat. Per 100 g, that's 40 kcal.
Values are for Onions, raw. Amounts vary with size, variety and preparation.
Onion
Per 1 medium (110 g)
Source: USDA FoodData Central.
Calories in an onion by serving
| Serving | Weight | Calories | Protein | Carbs | Fat |
|---|---|---|---|---|---|
| 100 g | 100 g | 40 | 1.1 g | 9.3 g | 0.1 g |
| 1 cup, chopped | 160 g | 64 | 1.8 g | 14.9 g | 0.2 g |
| 1 cup, sliced | 115 g | 46 | 1.3 g | 10.7 g | 0.1 g |
| 1 tbsp chopped | 10 g | 4 | 0.1 g | 0.9 g | 0 g |
| 1 large | 150 g | 60 | 1.7 g | 14 g | 0.2 g |
| 1 slice, large (1/4" thick) | 38 g | 15 | 0.4 g | 3.5 g | 0 g |
| 1 medium (2-1/2" dia) | 110 g | 44 | 1.2 g | 10.3 g | 0.1 g |
| 1 slice, medium (1/8" thick) | 14 g | 6 | 0.2 g | 1.3 g | 0 g |
| 1 small | 70 g | 28 | 0.8 g | 6.5 g | 0.1 g |
| 1 oz | 28 g | 11 | 0.3 g | 2.6 g | 0 g |
Where the calories come from
Protein 10%Carbs 88%Fat 2%
Onion has a very low energy density (0.4 kcal per gram). It provides 2.8 g of protein per 100 kcal.
Vegetables: calories compared
| Per 100 g | Calories | Protein | Carbs | Fat |
|---|---|---|---|---|
| Celery | 14 | 0.7 g | 3 g | 0.2 g |
| Cucumber | 15 | 0.7 g | 3.6 g | 0.1 g |
| Zucchini | 17 | 1.2 g | 3.1 g | 0.3 g |
| Romaine lettuce | 17 | 1.2 g | 3.3 g | 0.3 g |
| Tomato | 18 | 0.9 g | 3.9 g | 0.2 g |
| Asparagus | 20 | 2.2 g | 3.9 g | 0.1 g |
| Mushrooms | 22 | 3.1 g | 3.3 g | 0.3 g |
| Spinach | 23 | 2.9 g | 3.6 g | 0.4 g |
| Cauliflower | 25 | 1.9 g | 5 g | 0.3 g |
| Red bell pepper | 26 | 1 g | 6 g | 0.3 g |
| Green beans | 31 | 1.8 g | 7 g | 0.2 g |
| Broccoli | 34 | 2.8 g | 6.6 g | 0.4 g |
| Onion | 40 | 1.1 g | 9.3 g | 0.1 g |
| Carrots | 41 | 0.9 g | 9.6 g | 0.2 g |
| Green peas | 78 | 5.2 g | 14.3 g | 0.3 g |
| Sweet potato | 90 | 2 g | 20.7 g | 0.1 g |
| Baked potato | 93 | 2.5 g | 21.1 g | 0.1 g |
| Corn on the cob | 96 | 3.4 g | 21 g | 1.5 g |
Log it in seconds
In C for Calories, photograph your plate and an onion is estimated along with everything else on it, or search for it and enter the amount in grams. For packaged versions, scan the barcode to use the label.
Source: U.S. Department of Agriculture, Agricultural Research Service. FoodData Central, SR Legacy, FDC ID 170000. Calories are rounded to the nearest whole number and nutrients to one decimal place.
FAQ
Frequently asked questions
How many calories are in an onion?
44 calories in 1 medium (110 g), or 40 calories per 100 g.
How much protein is in an onion?
1.2 g of protein in 1 medium (110 g) (1.1 g per 100 g).
How many carbs are in an onion?
10.3 g of carbohydrates in 1 medium (110 g), including 1.9 g of fiber.