Calories in
onions, raw
40 kcal per 100 g Onions, raw contains 40 calories per 100 grams, or about 64 calories per cup, chopped. Per 100 g it provides 1.1 g protein, 9.3 g carbohydrate and 0.1 g fat.
By calories that splits 88% carbohydrate, 10% protein, 2% fat.
Calories in a typical serving
Per-100 g figures are useful for comparison but nobody eats 100 g of anything on purpose. These are the USDA's own household measures.
| Serving | Grams | Calories | Protein | Carbs | Fat |
|---|---|---|---|---|---|
| 1 cup, chopped | 160.0 g | 64 | 1.8 g | 14.9 g | 0.2 g |
| 1 cup, sliced | 115.0 g | 46 | 1.3 g | 10.7 g | 0.1 g |
| 1 tbsp chopped | 10.0 g | 4 | 0.1 g | 0.9 g | 0.0 g |
| 1 large | 150.0 g | 60 | 1.7 g | 14.0 g | 0.2 g |
Full nutrition, per 100 g and per cup, chopped
| Nutrient | Per 100 g | Per cup, chopped |
|---|---|---|
| Energy | 40 kcal | 64 kcal |
| Protein | 1.1 g | 1.8 g |
| Total fat | 0.1 g | 0.2 g |
| Saturated fat | 0.0 g | 0.1 g |
| Carbohydrate | 9.3 g | 14.9 g |
| Fibre | 1.7 g | 2.7 g |
| Sugars | 4.2 g | 6.8 g |
| Sodium | 4.0 mg | 6.4 mg |
| Potassium | 146.0 mg | 233.6 mg |
| Calcium | 23.0 mg | 36.8 mg |
| Iron | 0.2 mg | 0.3 mg |
| Vitamin C | 7.4 mg | 11.8 mg |
| Vitamin A | 0.0 µg | 0.0 µg |
| Cholesterol | 0.0 mg | 0.0 mg |
| Water | 89.1 g | 142.6 g |
USDA FoodData Central, SR Legacy (FDC ID 170000). A dash means the nutrient was not measured for this item, which is not the same as zero.
How onions, raw compares
Among the 209 vegetables and vegetable products items on this site, onions, raw ranks 88 of 209 by calorie density, against a category average of 62 kcal per 100 g — so it is about 35% less calorie-dense than typical for its group.
It carries 2.8 g of protein per 100 calories, so it is not a meaningful protein source.
To burn off one cup, chopped (64 kcal), a 70 kg adult would walk for roughly 13 minutes — see the walking calculation on our sister site, or pick a different activity. Treat that as a sense of scale rather than a rule: eating and moving are not a simple ledger.
Questions
How many calories are in onions, raw?
Onions, raw contains 40 calories per 100 g, which works out to about 64 calories per cup, chopped. It also provides 1.1 g of protein, 9.3 g of carbohydrate and 0.1 g of fat per 100 g.
What is the macro breakdown of onions, raw?
By calories, onions, raw is roughly 88% carbohydrate, 10% protein and 2% fat. That makes it a predominantly carbohydrate-based food.
How long does it take to burn off a cup, chopped?
About 13 minutes of ordinary walking for a 70 kg adult (MET 4.0). That is a rough guide for scale, not a prescription — appetite and activity interact in ways a simple subtraction does not capture.
Is this figure exact for the onions, raw I bought?
No. These are USDA reference values, averaged across samples. Real foods vary with variety, ripeness, growing conditions, cut, brand and how they were cooked — 10–20% either way is normal. Use them for planning, not precision.
Similar foods
Closest in calorie density within vegetables and vegetable products.
Source: USDA FoodData Central, SR Legacy — public domain. Full USDA description: "Onions, raw". General information only — not medical or nutrition advice. Values are averages for a food type and vary by brand, ripeness and preparation.