Carbs in Cooked Onion
Keto-friendlyHow many carbs are in cooked onion?
Cooked Onion has 1.4g net carbs per 100g — 8g total carbs minus 6.6g fiber — plus 1g protein, 0.1g fat, and 35 calories. That makes cooked onion very low in net carbs and lower than the typical vegetable, which averages about 17.9g net carbs per 100g. With this carb count, cooked 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 Open Food Facts; 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 cooked onion keto-friendly?
Yes — cooked onion is keto-friendly. It has 1.4g net carbs per 100g (8g total carbs − 6.6g 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) | 1.4g | 8g | 1g | 35 |
| 1 oz (28 g) | 0.4g | 2.2g | 0.3g | 10 |
How many calories are in cooked onion?
Cooked Onion has 35 calories per 100g. That's alongside 1g protein, 0.1g fat, and 1.4g net carbs per 100g.
Nutrition facts
| Nutrient | Amount (per 100 g) |
|---|---|
| Calories | 35 |
| Total carbs | 8g |
| Net carbs | 1.4g |
| Fiber | 6.6g |
| Sugar | 6.2g |
| Sugar alcohols | 0g |
| Protein | 1g |
| Fat | 0.1g |
| Sodium | 40mg |
| Potassium | 0mg |
Source: Open Food Facts (Marks and Spencer). Net carbs = total carbs − fiber − sugar alcohols, computed by CarbMeNot.
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Frequently asked questions
- How many carbs are in cooked onion?
- Cooked Onion has 8g of total carbs and 1.4g of net carbs per 100 grams.
- How many net carbs are in cooked onion?
- Cooked Onion has 1.4g of net carbs per 100 grams (total carbs 8g minus 6.6g fiber).
- Is cooked onion keto-friendly?
- Yes — cooked onion is keto-friendly. It has 1.4g net carbs per 100g (8g total carbs − 6.6g 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 cooked onion?
- Cooked Onion has 35 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.