Nutrition facts
Per 100 grams
- Energy
- 40 kcal167.4 kJ
- Carbohydrates
- 9.3 g
- Protein
- 1.1 g
- Total fat
- 0.1 g
- Dietary fiber
- 1.7 g
- Sodium
- 4 mg
- Calcium
- 23 mg
Nutrition referenceVegetables
Onion
Onions are pungent, layered bulbs used as a base flavor in cooking worldwide, eaten raw or cooked. Per 100 g they provide 40 calories with 9.3 g carbs and 1.7 g fiber.
40
kcalper 100g
- Carbs
- 9.3g
- Protein
- 1.1g
- Fat
- 0.1g
Reference values
About this food
Understanding this nutrition reference
Onions are round, layered bulbs with a pungent, savory flavor that mellows when cooked. They are a foundational ingredient in cooking worldwide, used raw in salads and salsas or sautéed, caramelized, and roasted as a base for soups, stews, and sauces.
Nutritionally, onions are low in calories and mostly water with natural sugars. Per 100 g they provide about 40 kcal, 9.3 g of carbohydrates, 1.1 g of protein, and 0.1 g of fat, with 1.7 g of dietary fiber, 4 mg of sodium, and 23 mg of calcium.
Onions vary in size and pungency by variety, but their nutrition per 100 g is similar. For accurate tracking, weigh the peeled onion and use the serving sizes below.
Portion guidance
How to use the serving references
Nutrition values are reported per 100 g. A typical medium onion (about 110 g) provides roughly 44 kcal. Use the serving sizes below to estimate portions when logging.
Questions and answers
Onion nutrition FAQ
How many calories are in an onion?
Onion provides about 40 calories per 100 g. A medium onion (about 110 g) provides roughly 44 calories.
Are onions high in carbs?
Onions provide about 9.3 g of carbohydrates per 100 g, mostly natural sugars, along with 1.7 g of fiber.
Do onions lose flavor when cooked?
Cooking softens onions and mellows their pungency, making them sweeter. Their calorie content per 100 g stays similar.
