Yellow onion calories come to 54 for one medium raw onion (143 g) and 38 per 100 g. Almost every one of those calories is carbohydrate, and the onion itself barely registers in a day of eating. The cooking fat is what changes the total: a cup of sautéed onion logs 107 calories, nearly double a whole raw onion.
54kcal
1 medium onion · 143 g, raw
9%protein
1.2 gProtein
12 gCarbs
0.1 gFat
How to burn off 54 kcal
—Walking, brisk
—Jogging
—Cycling, moderate
—Swimming
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Nutrition facts
Raw · per 143 g
Calories
54 kcal
Protein
1.2 g
Carbohydrate
12.3 g
Fat
0.1 g
Sodium
1 mg
Potassium
260 mg
Iron
0.4 mg
Source: USDA FoodData Central
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Verified nutrition data
Numbers on this page come from USDA FoodData Central, the U.S. Department of Agriculture’s food composition database, and from manufacturer labels where a branded product is named. Last verified September 2026. How we verify our data →
Yellow onion: calories, protein and sodium by serving
Percent of daily value uses the FDA reference of 2,000 kcal a day.
Serving
kcal
Protein
Carbs
Fat
Sodium
% DV kcal
1 medium (143 g)
54
1.2 g
12.3 g
0.1 g
1 mg
3%
100 g
38
0.8 g
8.6 g
0.1 g
1 mg
2%
Sauteed cup (87 g)
107
0.8 g
6.8 g
9.4 g
10 mg
5%
3 oz portion (85 g)
32
0.7 g
7.3 g
0 g
1 mg
2%
3 × 1 medium (143 g)
163
3.6 g
4 mg
5 × 1 medium (143 g)
272
5.9 g
7 mg
A medium onion is a 54-calorie ingredient
A medium yellow onion weighs about 143 g and carries 54 calories, which is 3% of the daily value. Most recipes call for one, and most cooks never think twice about it. They are right not to. A 3 oz portion (85 g), roughly a generous handful of chopped onion on a burger or in a salad, is just 32 calories.
Scaling up stays gentle. Two medium onions (286 g) come to 109 calories, three (429 g) to 163, and five (715 g) to 272. That last amount is a big pot of onion soup or a full tray of roasted vegetables, and the onion share of the total stays modest even then.
Sodium does not scale in any meaningful way either: five medium onions carry 7 mg. If you track portions loosely, onion is one of the safest foods to eyeball, and a few grams either way will not move your log. The calorie risk sits in what goes into the pan with it, not in the onion you chopped.
Carbs supply 90% of the calories
Per 100 g, raw yellow onion has 8.6 g of carbs, 0.8 g of protein and 0.1 g of fat. Run that through the calorie split and carbs account for 90% of the energy, protein 9% and fat 1%. Nearly every calorie is carbohydrate, and there is very little of anything else.
That carb load is small in absolute terms. A whole medium onion holds 12.3 g of carbs, and 2.7 g of that is fiber, a small but real step toward the 28 g daily value. Per 100 g the fiber figure is 1.9 g, so a heaping scoop of onion in a stir-fry or chili quietly adds to the day's total.
Protein is a footnote: 1.2 g in a medium onion, 2% of the daily value. Onion is a flavor ingredient, not a protein source, and it will not do much to keep you full on its own. Its real job is making lean protein, beans and vegetables taste like more, which is worth a lot for 54 calories.
The pan, not the onion, sets the sautéed number
The USDA sautéed row tells the real story. A cup of sautéed onion weighs 87 g and logs 107 calories with 9.4 g of fat, or 5% of the daily calorie value. A raw 3 oz portion of nearly the same weight (85 g) has 32 calories and 0 g of fat.
The onion did not change; the pan did. The sautéed cup has 6.8 g of carbs, slightly less than the 7.3 g in the raw portion, which tells you the extra energy is fat picked up during cooking, not anything the onion added. Sodium rises to 10 mg, which is still trivial.
If you count calories, log the oil or butter as its own line and measure it instead of pouring from the bottle. Using less fat in the pan saves far more than skipping the onion ever could. Softening onions with a splash of water, roasting them on a lined tray or simmering them in soup keeps the number close to the raw figures.
A cheap way to add volume and flavor
At 38 calories per 100 g, yellow onion is one of the easiest ways to bulk up a dish without bulking up the log. Folding a medium onion into a pan of ground turkey, lentils or scrambled eggs adds 54 calories along with real volume, texture and savory flavor.
It also brings 182 mg of potassium per 100 g and almost no sodium, at 1 mg. If you watch salt, that makes onion a useful tool: a well-browned onion adds depth that can let you go lighter on the shaker and on salty sauces.
Yellow onions are sold whole and pre-diced, from store brands like ShopRite and Hannaford to Table Fresh diced packs. Whole or diced, the numbers follow the weight, so a kitchen scale beats guessing. BodyPal can log an onion-heavy dish from a photo, which helps when the oil, not the onion, is the part you cannot see.
How does yellow onion compare?
Here is how yellow onion stacks up against red, white and sweet onions, per 100 g and per usual serving.
Verdict: For the lightest pick, sweet onion wins at 32 calories per 100 g, with white onion at 35 and yellow at 38. Red onion is the densest at 44 per 100 g, but the gaps are so small that you should choose by flavor and recipe, not by calories.
Most popular yellow onion brands in the United States
Ranked by popularity in the BodyPal database
# Productkcal / 100 g
1Vega Produce Yellow Onion1 cup · 160 g40 kcal
2Ahold Yellow Onion5.3 oz · 148 g30 kcal
3Hannaford Yellow Onions1 medium onion · 148 g41 kcal
4Table Fresh Yellow Onion Diced170 g41 kcal
5ShopRite Yellow Onions148 g41 kcal
6BJ's Wholesale Club Fresh Yellow Onion1 medium onion · 148 g30 kcal
7Papa John's Salads & Produce Diced Yellow Onions3 oz · 85 g41 kcal
A medium raw yellow onion (143 g) is about 54 calories. Per 100 g, raw yellow onion has 38 calories.
Is yellow onion good for weight loss?
A medium onion adds 54 calories, 2.7 g of fiber and almost no fat at 0.1 g. Sauteing changes that: a cup of sauteed yellow onion is 107 calories, with 9.4 g of fat from the cooking fat.
Yellow onion vs sweet onion: which has fewer calories?
Raw yellow onion is 38 calories per 100 g and sweet onion is 32, so the difference over a medium 143 g onion is only a few calories.
How many carbs are in a yellow onion?
A medium raw yellow onion (143 g) has 12.3 g of carbs, 2.7 g of it fiber. Per 100 g that is 8.6 g of carbs and 1.9 g of fiber.
How many calories are in half a yellow onion?
Half a medium yellow onion comes in under the 32 calories of a 3 oz portion (85 g), because half of a 143 g onion weighs less than 85 g. Weigh it if you want the exact figure: yellow onion runs 38 calories per 100 g.
What are the nutrition facts for 1 medium yellow onion?
One medium yellow onion (143 g) has 54 calories, 12.3 g of carbs, 2.7 g of fiber, 1.2 g of protein, 0.1 g of fat and 1 mg of sodium. That is 3% of the daily calorie value.
How many calories are in 100 g of yellow onion?
100 g of raw yellow onion has 38 calories, with 8.6 g of carbs, 1.9 g of fiber, 0.8 g of protein and 0.1 g of fat. Carbs supply 90% of those calories.
Does a medium onion have the same calories whether it's yellow or white?
No. A medium yellow onion (143 g) has 54 calories, while a medium white onion (113 g) has 40. Most of the gap is size: per 100 g, yellow has 38 and white has 35.
How many calories are in a large yellow onion?
A large yellow onion has more than the 54 calories of a medium 143 g onion. At 38 calories per 100 g, each extra 100 g of onion adds 38 calories, so weighing it gives the most accurate number.
