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Red onion (half) Calories
Rich in antioxidants, low calorie, source of vitamin C and fiber
In season: Spring · Summer · Autumn · Winter
CALORIES · 100 G
GI
POTASSIUM · 100 G
FIBER · 100 G
Quick answer
½ piece (half) of Red onion (half) (60 g) has 24 calories. That works out to 40 calories per 100 g. It contains 5.6 g of carbs, 0.7 g of protein, 0.1 g of fat and 1 g of fiber. Its 4.4 mg of Vitamin C covers 5% of the Daily Value. Its glycemic index is 15 (low), so it raises blood sugar slowly.
Red onion (half) Nutrition Facts
Selected: ½ piece (half) · 60 g
24
KCAL / 60G
Carbs
5.6g
· 2% DV
Protein
0.7g
· 1% DV
Fat
0.1g
· 0% DV
Fiber
1g
· 4% DV
DV is the share of the daily value covered, on a 2,000 kcal reference diet.
Calories come from: Carbs 86% · Protein 11% · Fat 3%
Red onion (half) nutrition facts table · ½ piece (half) (60 g)
| Nutrient | Amount | % DV |
|---|---|---|
| Calories | 24 kcal | |
| Total fat | 0.1 g | 0% |
| Saturated fat | 0.02 g | 0% |
| Trans fat | 0 g | |
| Sodium | 2.4 mg | 0% |
| Total carbohydrate | 5.6 g | 2% |
| Fiber | 1 g | 4% |
| Protein | 0.7 g | 1% |
Calories: Calories measure energy. Average daily need is 2,000 kcal. Excess calories are stored as fat, too few cause weight loss.
Carbs: Your body's primary energy source. The brain runs exclusively on carbs. Daily need: 275g.
Protein: Essential for muscle repair and cell growth. Daily need: 50g. Keeps you full and boosts metabolism.
Fat: Needed for hormone production and vitamin absorption. Daily need: 78g. Limit saturated fats, choose unsaturated.
Fiber: Critical for digestive health and satiety. Daily need: 28g. Stabilizes blood sugar, lowers cholesterol.
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How Many Calories in ½ Red onion (half)?
| Serving | Amount | Calories |
|---|---|---|
| ½ piece (half) | 60 g | 24 kcal |
| 1 tablespoon (shredded) | 10 g | 4 kcal |
| 1 slice (thin) | 15 g | 6 kcal |
| 2 tablespoon (diced) | 20 g | 8 kcal |
| 1 slice (thick) | 25 g | 10 kcal |
| 0.25 piece (quarter) | 30 g | 12 kcal |
| 100 g | 100 g | 40 kcal |
| 1 cup (chopped) | 115 g | 46 kcal |
| 1 piece (whole) | 120 g | 48 kcal |
Calculated from 40 calories per 100 g.
Frequently Asked Questions About Red onion (half)
Can you eat red onion raw?
Yes, red onion is commonly eaten raw in salads, sandwiches, and tacos. Its crisp texture and relatively mild, sweet flavor work well uncooked; slice it thinly, or soak the slices briefly in cold water for a gentler bite.
How do you stop red onions from making you cry?
Chill the red onion before cutting it and use a sharp knife, which damages fewer cells and releases fewer irritating compounds. Leave the root end intact until last, and cut near a vent or open window if your eyes are sensitive.
How should you store a cut red onion?
Wrap the cut surface or place the red onion in an airtight container in the refrigerator, then use it within a few days. Keep whole onions in a cool, dry, ventilated spot rather than a sealed plastic bag, where moisture can encourage spoilage.
How do you make quick-pickled red onions?
Slice a red onion thinly and cover it with a hot mixture of vinegar, water, salt, and a little sugar if desired. Let it cool, then refrigerate it in a clean jar; the slices add tang and crunch to tacos, sandwiches, and grain bowls.
Why does red onion turn blue or green when cooked?
Red onion pigments can change color when exposed to heat and shifts in acidity, so a blue-green tint can appear during cooking. It is usually a harmless color change; adding a little vinegar or lemon juice can help keep the onion more reddish.
What is the difference between red onion and yellow onion?
Red onion is often milder and more colorful when raw, making it popular in salads and toppings. Yellow onion has a stronger flavor raw and becomes sweet and savory as it cooks, so it is commonly used as a base for soups and stews.
Can you freeze red onion?
Yes, chop red onion and freeze it in an airtight container or freezer bag. Thawed onion loses some of its crisp texture, so save it for cooked dishes such as soups, sauces, and sautés rather than using it raw.
How do you mellow the taste of red onion for salads?
Slice the red onion thinly and soak it in cold water for several minutes, then drain it well. A brief soak softens its sharp flavor while keeping some crunch; lemon juice or vinegar also balances the bite in a salad.
Can you caramelize red onion?
Yes, red onion can be caramelized slowly in a pan with a little oil, stirring occasionally until soft and sweet. Its color may darken or turn less vivid as it cooks, but the resulting onions work well on burgers, toast, and roasted vegetables.
Can red onion cause gas or bloating?
Yes, red onion can cause gas or bloating in some people, particularly when eaten raw, because it contains fermentable carbohydrates. Try a smaller portion or cooked onion; if symptoms are persistent or severe, discuss them with a healthcare professional.
Red onion (half) Vitamins & Minerals
Vitamins
Vitamin C
4.44mg · 5% DV
B6
0.07mg · 4% DV
Folate
11.4µg · 3% DV
B1
0.03mg · 3% DV
Minerals
Manganese
0.08mg · 3% DV
Potassium ⭐
88mg · 3% DV
Copper
0.02mg · 2% DV
Phosphorus
17mg · 2% DV
Sodium
2.4mg · 0% DV
Red onion (half) Glycemic Index
GLYCEMIC INDEX
GLYCEMIC LOAD
Accounts for portion size — a more realistic measure than GI alone.
How to Burn Off Red onion (half)
To burn the 24 calories in ½ piece (half) (60 g):
🚶
Walking (5 km/h)
🏃
Running (8 km/h)
🚴
Cycling
🏊
Swimming
Times are calculated with the MET equation for a 70 kg adult. Actual burn varies with your weight, age and pace.
What is Red onion (half)?
Red onion has crisp, white flesh with purple-red rings and is often used raw as well as cooked. This portion is half an onion. In its place of origin and in kitchens worldwide, it is sliced into salads, salsas and sandwiches, or cooked until mellow in sauces, roasts and stir-fries. Its colour and mild sharpness make it an easy way to add freshness to a meal.
Raw, it tastes pleasantly pungent and crunchy; cooking brings out a sweeter, softer flavour. Red onion is low in calories and contributes fibre; it has 40 calories per 100 grams. Pair it with tomatoes, herbs, citrus or grilled foods. If its bite is too strong, slice it thinly and briefly rinse or soak it before serving.
How Nutritious Is Red onion (half)?
Nutrient density
Medium
How many vitamins, minerals and how much fiber this food carries per calorie. A high score means a lot of nutrition for few calories.
Satiety score
Medium
An EatBetter score computed from fiber, protein and calorie density. A high score means staying full longer on the same calories.
Both scores are calculated per 100 g and do not change with the selected portion. The satiety score is EatBetter's own calculation, not a clinical measure.
Is Red onion (half) Processed?
NOVA 1
Unprocessed
1. Unprocessed
2. Minimally Processed
3. Processed
4. Ultra-Processed
NOVA classifies foods into 4 groups by industrial processing. NOVA 1 (unprocessed) is the healthiest.
Does Red onion (half) Contain Allergens?
No known major allergens
Which Diets Is Red onion (half) Good For?
Vegan
✓ Suitable
Vegetarian
✓ Suitable
Gluten-Free
✓ Suitable
Dairy-Free
— Not suitable
Mediterranean
✓ Suitable
Paleo
✓ Suitable
Whole30
— Not suitable
DASH
— Not suitable
Keto
— Not suitable
Low FODMAP
— Not suitable
Red onion (half) Fat Profile
SATURATED
0.02g
MONOUNSATURATED
0.01g
POLYUNSATURATED
0.01g
Omega 6:3 ratio 1:1
Below the ideal 4:1 — a good omega balance.
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Nutrition data compiled from USDA FoodData Central and scientific sources.