How many carbs are in a Onion?
A 1 medium (110g) serving of Onion contains 10.1g of total carbs (8.2g net carbs), 4.7g sugar, 44 calories, 1.2g protein, 0.1g fat and 1.9g fiber.
- Calories
- 44 cal
- Carbohydrates
- 10.1 g
- of which Sugars
- 4.7 g
- Fiber
- 1.9 g
- Net carbs
- 8.2 g
- Protein
- 1.2 g
- Fat
- 0.1 g
Onion nutrition at a glance
Per 1 medium (110g), Onion delivers about 2% of a 2,000-calorie daily reference, 4% of the 275g daily carbohydrate reference and 7% of the 28g daily fiber reference. Sugar sits at 9% of the 50g added-sugar reference and protein contributes 2% of the 50g protein reference.
- Calories
- 40
- Carbs
- 9.2 g
- Sugar
- 4.3 g
- Protein
- 1.1 g
- Fat
- 0.1 g
- Fiber
- 1.7 g
Blood-sugar impact of Onion
Moderate glycemic impact expected. If you're monitoring blood sugar, keep an eye on total portion size and combine with protein or fat.
With 10.1g total carbs and 1.9g fiber, the net-carb figure for a 1 medium (110g) serving works out to roughly 8.2g — this is the number most keto and low-carb tracking apps use. If you're managing type 2 diabetes, pre-diabetes or reactive hypoglycemia, use total carbs for insulin dosing calculations and treat net carbs as a rough guide for meal planning.
Ways to eat Onion
- Great fit for low-carb, keto or diabetic-friendly meals — build around onion without worrying about a big glucose spike.
- Use onion as a satisfying snack between meals when you want to stay in a low-carb window.
- Combine onion with leafy greens and olive oil for a clean, blood-sugar-friendly plate.
Frequently asked questions
Is Onion keto-friendly?
In moderation. At 8.2g net carbs per 1 medium (110g), Onion can fit a keto plan but you'll want to watch total-day carbs.
How many carbs in Onion per 100 grams?
About 9.2g of carbs, 4.3g sugar and 40 calories per 100g of Onion.
How does Onion affect blood sugar?
Moderate glycemic impact expected. If you're monitoring blood sugar, keep an eye on total portion size and combine with protein or fat.
Is Onion good for weight loss?
A serving delivers 44 calories with 1.2g protein and 1.9g fiber. Foods that are relatively high in protein and fiber per calorie tend to be more filling — with a 7% combined protein-plus-fiber-to-calorie ratio, Onion is a solid pick for a satiating, weight-loss-friendly meal.
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Open scannerSources & how these numbers are calculated
Nutrition values are consensus averages compiled from the USDA FoodData Central database for a typical 1 medium (110g) serving of Onion. Actual values vary with brand, variety, ripeness and preparation — always check the label on packaged products. Daily-value percentages reference the U.S. FDA 2,000-calorie adult reference (275g carbs, 50g added sugar, 50g protein, 78g fat, 28g fiber).
Content reviewed by Carb Lens editorial. Read our editorial policy for how we source, review and update food data.