Carbs in Sweet Onion
Keto-friendlyHow many carbs are in sweet onion?
Sweet Onion has 6.6g net carbs per 100g — 7.5g total carbs minus 0.9g fiber — plus 0.8g protein, 0.1g fat, and 32 calories. That makes sweet onion relatively low in net carbs and lower than the typical vegetable, which averages about 17.9g net carbs per 100g. With this carb count, sweet onion fits a keto or low-carb diet (usually 20–50g net carbs per day) in normal portions. Values are per per 100 g, sourced from USDA FoodData Central; net carbs are computed by CarbMeNot.
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Last updated June 10, 2026 · Reviewed by Jordan Lee, Nutrition Editor
Values per 100 g.
Is sweet onion keto-friendly?
Yes, sweet onion can fit a keto diet in moderate portions. It has 6.6g net carbs per 100g (7.5g total carbs − 0.9g fiber). On a standard keto diet (20–50g net carbs per day), that leaves plenty of room for other vegetables and meals.
Carbs by serving size
| Serving | Net carbs | Total carbs | Protein | Calories |
|---|---|---|---|---|
| 100 g (3.5 oz) | 6.6g | 7.5g | 0.8g | 32 |
| 1 oz (28 g) | 1.8g | 2.1g | 0.2g | 9 |
How many calories are in sweet onion?
Sweet Onion has 32 calories per 100g. That's alongside 0.8g protein, 0.1g fat, and 6.6g net carbs per 100g.
Nutrition facts
| Nutrient | Amount (per 100 g) |
|---|---|
| Calories | 32 |
| Total carbs | 7.5g |
| Net carbs | 6.6g |
| Fiber | 0.9g |
| Sugar | 5g |
| Sugar alcohols | 0g |
| Protein | 0.8g |
| Fat | 0.1g |
| Sodium | 8mg |
| Potassium | 119mg |
Source: USDA FoodData Central (SR Legacy). Net carbs = total carbs − fiber − sugar alcohols, computed by CarbMeNot.
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Frequently asked questions
- How many carbs are in sweet onion?
- Sweet Onion has 7.5g of total carbs and 6.6g of net carbs per 100 grams.
- How many net carbs are in sweet onion?
- Sweet Onion has 6.6g of net carbs per 100 grams (total carbs 7.5g minus 0.9g fiber).
- Is sweet onion keto-friendly?
- Yes, sweet onion can fit a keto diet in moderate portions. It has 6.6g net carbs per 100g (7.5g total carbs − 0.9g fiber). On a standard keto diet (20–50g net carbs per day), that leaves plenty of room for other vegetables and meals.
- How many calories are in sweet onion?
- Sweet Onion has 32 calories per 100 grams.
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CarbMeNot provides general nutrition information, not medical advice. Values are estimates — verify before relying on them for any health decision. See our Medical Disclaimer.