Calories in Onion, raw
Generic food Raw Vegetables
Onion, raw contains 40 kcal per 100 g. A typical serving of 1 slice, medium, 1/8" thick (14 g) provides about 6 kcal.
Roughly 88% of its calories come from carbohydrates, with 10% from protein and 2% from fat (estimated with general energy factors).
That is more energy than the typical item in vegetables and vegetable products on FoodFactly, where the median is 35 kcal per 100 g across 866 foods.
These values are for the raw food. Cooking changes the water content and some nutrients, so cooked versions are listed separately below.
The data comes from USDA FoodData Central: SR Legacy.
Nutrition facts
| Nutrient | Amount per 100 g | % DV |
|---|---|---|
| Calories C | 40 kcal | |
| Total fat C | 0.1 g | 0.1% |
| Saturated fat C | 0.042 g | 0.2% |
| Trans fat Z | 0 g | |
| Cholesterol Z | 0 mg | 0% |
| Sodium C | 4 mg | 0.2% |
| Total carbohydrates C | 9.3 g | 3% |
| Dietary fiber ? | 1.7 g | 6% |
| Total sugars C | 4.2 g | |
| Protein C | 1.1 g | 2% |
| Vitamin A C | 0 µg | 0% |
| Vitamin C ? | 7.4 mg | 8% |
| Vitamin D Z | 0 µg | 0% |
| Vitamin E C | 0.02 mg | 0.1% |
| Vitamin K C | 0.4 µg | 0.3% |
| Thiamin (B1) C | 0.046 mg | 4% |
| Riboflavin (B2) C | 0.027 mg | 2% |
| Niacin (B3) C | 0.12 mg | 0.7% |
| Pantothenic acid (B5) C | 0.12 mg | 2% |
| Vitamin B6 C | 0.12 mg | 7% |
| Folate (B9) C | 19 µg | 5% |
| Vitamin B12 Z | 0 µg | 0% |
| Choline ? | 6.1 mg | 1% |
| Calcium C | 23 mg | 2% |
| Iron C | 0.21 mg | 1% |
| Magnesium C | 10 mg | 2% |
| Phosphorus C | 29 mg | 2% |
| Potassium C | 146 mg | 3% |
| Zinc C | 0.17 mg | 2% |
| Copper C | 0.039 mg | 4% |
| Manganese C | 0.13 mg | 6% |
| Selenium C | 0.5 µg | 0.9% |
| Fluoride M | 1.1 µg |
% DV: percent of the FDA Daily Value for adults (reference amounts). Letters show how each value was obtained: M measured, C calculated, L label, Z assumed zero, I imputed. Vitamins and minerals not listed were not reported by the source.
Nutritional breakdown
- Protein 10%
- Carbohydrates 88%
- Fat 2%
Approximate share of calories, using general energy factors (4 kcal/g protein and carbohydrate, 9 kcal/g fat, 7 kcal/g alcohol).
Vitamins and minerals, % Daily Value per 100 g
Nutritional insights
- Protein1.1 gin the lowest quarter of vegetables and vegetable products (median 2 g)
- Fiber1.7 gbelow the median for vegetables and vegetable products (median 2.2 g)
- Sugars4.2 gin the top quarter of vegetables and vegetable products (median 2.3 g)
- Fat0.1 gin the lowest quarter of vegetables and vegetable products (median 0.3 g)
- Saturated fat0.042 gbelow the median for vegetables and vegetable products (median 0.052 g)
- Sodium4 mgin the lowest quarter of vegetables and vegetable products (median 36 mg)
- Protein per 100 kcal2.8 gprotein density, useful for comparing foods with different calorie levels
- Water89.1 gwater per 100 g, which largely explains differences between raw, cooked and dried forms
Full nutrient profile
Fats and cholesterol (2)
| Monounsaturated fat C | 0.013 g |
|---|---|
| Polyunsaturated fat C | 0.017 g |
Sugars and starch (7)
| Starch M | 0 g |
|---|---|
| Sucrose C | 0.99 g |
| Glucose C | 2 g |
| Fructose C | 1.3 g |
| Lactose C | 0 g |
| Maltose C | 0 g |
| Galactose Z | 0 g |
Amino acids (18)
| Tryptophan M | 0.014 g |
|---|---|
| Threonine M | 0.021 g |
| Isoleucine M | 0.014 g |
| Leucine M | 0.025 g |
| Lysine M | 0.039 g |
| Methionine M | 0.002 g |
| Cystine M | 0.004 g |
| Phenylalanine M | 0.025 g |
| Tyrosine M | 0.014 g |
| Valine M | 0.021 g |
| Arginine M | 0.1 g |
| Histidine M | 0.014 g |
| Alanine M | 0.021 g |
| Aspartic acid M | 0.091 g |
| Glutamic acid M | 0.26 g |
| Glycine M | 0.025 g |
| Proline M | 0.012 g |
| Serine M | 0.021 g |
Individual fatty acids (29)
| EPA (omega-3, 20:5 n-3) M | 0 g |
|---|---|
| DHA (omega-3, 22:6 n-3) M | 0 g |
| Linoleic acid (omega-6, 18:2) M | 0.013 g |
| SFA 4:0 ? | 0 g |
| SFA 6:0 ? | 0 g |
| SFA 8:0 M | 0 g |
| SFA 10:0 M | 0 g |
| SFA 12:0 M | 0 g |
| SFA 14:0 M | 0.004 g |
| SFA 16:0 M | 0.034 g |
| SFA 18:0 M | 0.004 g |
| SFA 20:0 M | 0 g |
| MUFA 18:1 M | 0.013 g |
| PUFA 18:3 M | 0.004 g |
| PUFA 20:4 M | 0 g |
| SFA 22:0 M | 0 g |
| MUFA 14:1 M | 0 g |
| MUFA 16:1 M | 0 g |
| PUFA 18:4 M | 0 g |
| MUFA 20:1 M | 0 g |
| MUFA 22:1 M | 0 g |
| PUFA 22:5 n-3 (DPA) M | 0 g |
| SFA 15:0 M | 0 g |
| SFA 17:0 M | 0 g |
| SFA 24:0 M | 0 g |
| PUFA 20:2 n-6 c,c M | 0 g |
| MUFA 17:1 M | 0 g |
| PUFA 20:3 M | 0 g |
| MUFA 15:1 M | 0 g |
Carotenoids (14)
| Beta-carotene I | 1 µg |
|---|---|
| Lycopene I | 0 µg |
| Lutein + zeaxanthin I | 4 µg |
| Retinol Z | 0 µg |
| Carotene, alpha I | 0 µg |
| Vitamin D (D2 + D3), International Units Z | 0 IU |
| Cryptoxanthin, beta I | 0 µg |
| Tocopherol, beta C | 0 mg |
| Tocopherol, gamma C | 0 mg |
| Tocopherol, delta C | 0 mg |
| Tocotrienol, alpha C | 0.04 mg |
| Tocotrienol, beta C | 0 mg |
| Tocotrienol, gamma C | 0 mg |
| Tocotrienol, delta C | 0 mg |
Sterols (1)
| Phytosterols ? | 15 mg |
|---|
Other components (13)
| Water C | 89.1 g |
|---|---|
| Alcohol ? | 0 g |
| Caffeine Z | 0 mg |
| Ash C | 0.35 g |
| Theobromine Z | 0 mg |
| Energy C | 166 kJ |
| Vitamin A, IU C | 2 IU |
| Vitamin K (Dihydrophylloquinone) M | 0 µg |
| Folic acid Z | 0 µg |
| Folate, food ? | 19 µg |
| Betaine M | 0.1 mg |
| Vitamin E, added Z | 0 mg |
| Vitamin B-12, added Z | 0 µg |
Values by source
More than one dataset describes this food. FoodFactly keeps each source's values separately instead of blending them. The headline values above come from USDA FoodData Central: SR Legacy.
| Per 100 g | USDA FNDDS |
|---|---|
| Calories | 38 kcal |
| Protein | 0.86 g |
| Carbohydrates | 8.5 g |
| Fat | 0.08 g |
| Fiber | 1.7 g |
| Sugars | 5.8 g |
| Sodium | 1 mg |
Other forms of Onion
Raw, cooked, dried and processed versions are separate records with their own measured values.
| Food | Calories | Protein | Carbs | Fat |
|---|---|---|---|---|
| Onions, cooked, boiled, drained, without salt Cooked | 44 | 1.4 g | 10.2 g | 0.19 g |
| Onions, dehydrated flakes Dried or dry | 349 | 9 g | 83.3 g | 0.46 g |
| Onions, canned, solids and liquids Canned | 19 | 0.85 g | 4 g | 0.09 g |
| Onions, yellow, sauteed Cooked | 123 | 0.95 g | 7.9 g | 10.8 g |
| Onions, spring or scallions (includes tops and bulb), raw Raw | 32 | 1.8 g | 7.3 g | 0.19 g |
| Onions, young green, tops only | 27 | 0.97 g | 5.7 g | 0.47 g |
| Onions, welsh, raw Raw | 34 | 1.9 g | 6.5 g | 0.4 g |
| Onions, sweet, raw Raw | 32 | 0.8 g | 7.6 g | 0.08 g |
| Onions, cooked, boiled, drained, with salt Cooked | 42 | 1.4 g | 9.6 g | 0.19 g |
| Onions, frozen, chopped, cooked, boiled, drained, with salt Cooked | 26 | 0.77 g | 6 g | 0.1 g |
| Onions, frozen, chopped, unprepared Frozen | 29 | 0.79 g | 6.8 g | 0.1 g |
| Onions, frozen, chopped, cooked, boiled, drained, without salt Cooked | 28 | 0.77 g | 6.6 g | 0.1 g |
Per 100 g. Calories in kcal. n/a: not reported by the source.
Foods with a similar nutritional profile
| Food | Calories | Protein | Carbs | Fat |
|---|---|---|---|---|
| Carrots, raw Raw | 41 | 0.93 g | 9.6 g | 0.24 g |
| Red bell pepper, raw Raw | 26 | 0.99 g | 6 g | 0.3 g |
| Green beans, raw Raw | 31 | 1.8 g | 7 g | 0.22 g |
| Cabbage, raw Raw | 25 | 1.3 g | 5.8 g | 0.1 g |
| Rutabagas, raw Raw | 37 | 1.1 g | 8.6 g | 0.16 g |
| Eggplant, raw Raw | 25 | 0.98 g | 5.9 g | 0.18 g |
| Peppers, hot chili, green, raw Raw | 40 | 2 g | 9.5 g | 0.2 g |
| Cabbage, red, raw Raw | 31 | 1.4 g | 7.4 g | 0.16 g |
Per 100 g. Calories in kcal. n/a: not reported by the source.
Compare: Beets, raw vs Onion, rawOnion, raw vs Carrots, rawOnion, raw vs Red bell pepper, raw
Frequently asked questions
How many calories are in raw onion?
100 g of raw onion has 40 kcal. 1 slice, medium, 1/8" thick (14 g): about 6 kcal. 1 slice, thin (9 g): about 4 kcal. 1 tbsp chopped (10 g): about 4 kcal.
How much protein is in raw onion?
Raw onion contains 1.1 g of protein per 100 g (2% of the 50 g Daily Value), or 0.15 g in 1 slice, medium, 1/8" thick (14 g). About 10% of its calories come from protein. Compared with other vegetables and vegetable products, that is in the lowest quarter (median 2 g).
How many carbs are in raw onion?
Raw onion has 9.3 g of total carbohydrates per 100 g, including 1.7 g of fiber and 4.2 g of sugars.
How much fat is in raw onion?
Raw onion contains 0.1 g of fat per 100 g, of which 0.042 g is saturated (0.2% of the Daily Value).
How much sodium is in raw onion?
100 g contains 4 mg of sodium, 0.2% of the 2,300 mg Daily Value.
Does onion have the same nutrition raw and cooked?
No. Per 100 g, onion, raw has 40 kcal, while onions, cooked, boiled, drained, without salt has 44 kcal. Cooking changes the water content, so always use the record that matches how you weigh the food.
Where does this nutrition data come from?
From USDA FoodData Central: SR Legacy, record dated April 1, 2019. FoodFactly last checked it on November 6, 2026. Each value above shows whether it was measured, calculated or taken from a label.
Source of the nutrition information
- USDA FoodData Central: SR Legacy, record 170000. License: CC0 1.0 (U.S. public domain). Source record dated April 1, 2019. Imported November 6, 2026.
Last updated: . Source description: "Onions, raw". Data quality score: 100/100 (how it is calculated).
General nutrition information, not medical advice. Individual needs differ; see our disclaimer.