How many carbs are in onions?
1 slice, large (1/4" thick) of onions contains about 3.2g of carbohydrate, 2.8g net carbs after subtracting 0.4g of fiber, 0.4g of protein, and 14 calories.
Carbs by portion size
| Portion | Total carbs | Fiber | Net carbs |
|---|---|---|---|
| 1 slice, thin (8g) | 0.8g | 0.1g | 0.7g |
| 1 slice, medium (1/8" thick) (12g) | 1.2g | 0.2g | 1.1g |
| 1 tbsp chopped (15g) | 1.5g | 0.2g | 1.3g |
| 1 slice, large (1/4" thick) (32g) | 3.2g | 0.4g | 2.8g |
| 1 small (60g) | 6.1g | 0.8g | 5.3g |
| 1 medium (94g) | 9.5g | 1.3g | 8.2g |
Net carbs in onions
1 slice, large (1/4" thick) of onions contains 2.8g of net carbs — total carbs (3.2g) minus dietary fiber (0.4g). Net carbs are the carbs your body actually digests and that raise blood glucose. See our guide to net carbs for how this calculation works and when to use it.
Full nutrition for onions (per 100g)
- Calories: 44 kcal
- Carbohydrate: 10.2g
- Dietary fiber: 1.4g
- Sugars: 4.7g
- Protein: 1.4g
- Fat: 0.2g
Reference values from USDA FoodData Central (sr legacy dataset, fdcId 170001). Values are per 100 grams.
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Download on the App StoreFrequently asked questions
How many carbs are in onions?
1 slice, large (1/4" thick) of onions contains about 3.2g of total carbohydrate. After subtracting 0.4g of fiber, the net carbs are about 2.8g.
How many net carbs are in onions?
Net carbs in 1 slice, large (1/4" thick) of onions are about 2.8g — that is total carbs (3.2g) minus dietary fiber (0.4g). See our net carbs explainer for the full calculation.
Is onions good for diabetics?
Onions contains carbohydrates that will raise blood glucose. Whether it fits your meal plan depends on the portion and your overall daily target. Most U.S. diabetes care teams use total carbs (not net) for insulin dosing — see our diabetes carb-counting guide.
Is onions keto-friendly?
Whether onions fits a keto plan depends on your daily net-carb budget (typically under 20–30g per day). One serving (1 slice, large (1/4" thick)) provides about 2.8g of net carbs.