How much protein is in Onions?

Onions contains 0.92g of protein per 100g. This is 2% of the recommended daily value of 50g.

🥦 onion

Calories in Onions

Q: How many calories are in Onions?

Onions contains 42 calories per 100g. A typical serving of 100g (100g) provides 42 calories.

Q: How many carbs are in Onions?

Onions contains 10.11g of carbohydrates per 100g.

Q: Is Onions good for weight loss?

Onions has 42 calories per 100g. With fewer than 50 kcal per 100g, it is a very low-calorie food and can be included freely in most weight-loss diets.

Why onions add flavour for almost no calories

42 kcal

per 100g

Protein 0.92g

Carbs 10.11g

Fat 0.08g

What makes onions so powerful?

Onions carry only about 40 calories per 100 g, so they are one of the cheapest ways to build flavour in a dish. Cooking them softens the sharp sulfur compounds and brings out natural sugars, which is why caramelised onions taste sweet. The calories only go up if you cook them in a lot of oil or butter. They are also a source of fibre and the antioxidant quercetin.

🧅

About 40 kcal per 100 g

A medium onion is around 110 g.

🍳

Oil is the calories

Caramelising in butter adds more than the onion.

🌿

Quercetin

An antioxidant found in the outer layers.

💡 When & how to use it

Sweat in a teaspoon of oil or a splash of water. Add to soups, chilli and omelettes for volume.

Calories by Serving Size

100g

42 kcal

P 0.92g C 10.11g F 0.08g

200g

84 kcal

P 1.8g C 20.2g F 0.2g

50g

21 kcal

P 0.5g C 5.1g F 0g

Full Nutrition Facts

Per 100g — daily values based on a 2,000 calorie diet

Nutrition Facts

Serving size: 100g

Calories 42

% Daily Value*

Total Fat 0.08g 0%

Trans Fat g

Total Carbohydrate 10.11g 4%

Protein 0.92g 2%

* Percent Daily Values are based on a 2,000 calorie diet. Your daily values may be higher or lower depending on your calorie needs.

How does Onions fit your daily goals?

🏃

8 min

Walking to burn 42 kcal

🎯

of 2,000 kcal daily goal

💪

0.92g

protein (2% of daily 50g)

⚡

servings until 2,000 kcal

🍎

Log Onions in CalRay — just snap a photo

CalRay's AI recognizes onions and hundreds of thousands of other foods from a photo. No manual lookup needed.

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Frequently Asked Questions

How many calories are in Onions?

Onions contains 42 calories per 100g. It is considered a very low-calorie food (under 50 kcal/100g), making it excellent for weight management.

How much protein does Onions have?

Onions provides 0.92g of protein per 100g, which is 2% of the 50g daily recommended value. It is not a primary protein source.

How many carbs are in Onions?

Onions contains 10.11g of carbohydrates per 100g .

Is Onions good for weight loss?

Yes! Onions is very low in calories (42 kcal/100g) and can be eaten in generous portions even on a calorie-restricted diet.

How do I track Onions calories accurately?

The easiest way to track onions is with CalRay. Simply snap a photo of your meal and the AI will automatically identify the food and calculate calories and macros based on the estimated portion size — no manual lookup required. You can also search by name and adjust gram weight manually.