Onion Nutrition Facts & Calories

100g of onions contain about 40 calories (kcal).
Calories per: ounce | one onion | slice | cup, sliced

For example, a medium size onion (110 g) contain about 44 calories.

This is about 2% of the daily caloric intake for an average adult with medium weight and activity level (assuming a 2000 kcal daily intake).

Onion key facts

The nutrients that matter most in fruit and vegetables, per 100 g, compared with carrot.

Nutrient (per 100 g)	Onion	Carrot a common vegetable
Sugar	4.2 g	–
Fiber	1.7 g	2.8 g
Vitamin C	7.4 mg	5.9 mg
Potassium	146 mg	320 mg

• Sugar: 4.7 g in a medium size onion, that is 1 sugar cube (4 g each).
• Onion has 25% more calories than the typical vegetable on this site (32 kcal per 100 g is the median of vegetables).

To visualize how much 44 kcal actually is, keep in mind that the calorie content of medium size onion is similar to that of, for example:

• 0.5 medium apple (96 kcal)
• 0.5 medium banana (116 kcal)
• 2 medium carrots (25 kcal each)
• 0.5 medium potato (69 kcal)

Take a quick look at the tables below for detailed information about onion nutrition.