How many calories are in a sweet onion?
One medium sweet onion weighs 148 g and holds 47 calories. Raw sweet onion runs 32 calories per 100 g, about as light as a vegetable gets while still tasting sweet. A whole large onion, the 331 g kind you grab loose from the bin, comes to 106.
You'd need to walk about 9 minutes to burn the 47 calories in one medium onion (148 g).
How long does it take to burn off sweet onion?
One medium onion (148 g) is 47 kcal. Enter your weight and the amount you ate to see how long it takes you to burn that off:
lb
| Activity | Time to burn 47 kcal |
|---|---|
| Walking, brisk | 9 min |
| Cycling, moderate | 6 min |
| Swimming, moderate | 7 min |
| Jogging | 6 min |
| Weight training, moderate | 10 min |
Times are for a 155 lb adult at a steady pace; change the weight to see yours. The amount is set to the portion in the text (148 g); change it to what you actually ate. BodyPal works this out from your steps automatically.
On this page
- Sweet onion quick facts
- US servings, from one ounce to a whole onion
- Vidalia and the numbers on the bag
- Cooked, pickled and stuffed into a sub
- Sweet without added sugar
- How does sweet onion compare?
- Most popular sweet onion brands
- Sweet onion FAQs
Sweet onion quick facts
The number people want is for the onion in their hand: a raw, unpeeled sweet onion off the produce shelf. That is USDA SR Legacy 170008, "Onions, sweet, raw", and its labeling serving of 148 g is exactly the "1 raw medium onion" printed on retail sweet onion bags. Every other USDA record carrying the words "sweet onion" is a different food entirely — a teriyaki sandwich, or a jar of sweetened relish — and those get their own sections below.
| Nutrient | Per 100 g | Per one medium onion (148 g) | % Daily Value |
|---|---|---|---|
| Calories | 32 | 47 | — |
| Total fat | 0.08 g | 0.1 g | 0% |
| Carbohydrate | 7.55 g | 11.2 g | 4% |
| Dietary fiber | 0.9 g | 1.3 g | 5% |
| Total sugars | 5.02 g | 7.4 g | — |
| Protein | 0.8 g | 1.2 g | 2% |
| Sodium | 8 mg | 12 mg | 1% |
% Daily Value is based on a 2,000-calorie diet.
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 →
Two label rows are missing on purpose. USDA doesn't report saturated fat or added sugars for this raw record, so there is nothing honest to put in those cells — and in a whole raw onion there is no added sugar to report anyway. Cholesterol is 0 mg, as it is in every plant food. Potassium is the one mineral worth naming: 119 mg per 100 g, or 176 mg in a medium onion, which is 4% of the 4,700 mg Daily Value the FDA sets.
US servings, from one ounce to a whole onion
| Serving | Weight | Calories |
|---|---|---|
| 1 oz | 28 g | 9 kcal |
| Half a medium onion | 74 g | 24 kcal |
| 4 oz raw | 113 g | 36 kcal |
| One medium onion | 148 g | 47 kcal |
| One large onion | 331 g | 106 kcal |
| Per 100 g | 100 g | 32 kcal |
Two of those weights come straight from USDA: the 148 g medium onion, which is the labeling serving, and the 331 g large onion. The 1 oz, 4 oz and half-onion lines are our own arithmetic from the USDA 100 g figure, not USDA servings.
Here is the trap. A recipe that says "one onion" and a nutrition label that says "one onion" are not the same object. The large onion USDA weighs is 331 g — more than double the 148 g medium, and 106 calories against 47. If you slice a whole big sweet onion onto a burger platter and log it as "1 medium onion," you're about 59 calories light. That's small on its own and not small across a week of cooking.
The good news is that the error is cheap either way. Even the large onion is 106 calories, less than a tablespoon of the oil you'd cook it in. Onions are one of the few foods where weighing is optional.
Vidalia and the numbers on the bag
Vidalia is a place, not a species — a protected growing region in Georgia — and Vidalias are sold as sweet onions. USDA's branded records for them don't match the raw SR Legacy row exactly, because label numbers are rounded and declared by the packer rather than measured in a lab.
| Version | Per 100 g | Typical piece | Calories |
|---|---|---|---|
| Sweet onion, raw (USDA SR Legacy) | 32 kcal | one medium onion, 148 g | 47 kcal |
| REALSWEET Vidalia sweet onions (label) | 41 kcal | one raw medium onion, 148 g | 61 kcal |
| REALSWEET sweet onions (label) | 30 kcal | one onion, 148 g | 44 kcal |
Look at the spread: two bags from the same brand, the same 148 g serving, and a 17-calorie gap between them. Neither is wrong. Label calories are computed from declared carbohydrate, protein and fat after FDA rounding rules, and onions vary by variety, size and how much water they've lost in storage.
Our pick for logging is the 47 from the SR Legacy row. It sits between the two labels, it's a measured value rather than a declared one, and it applies whether the onion in your basket is stamped Vidalia, Walla Walla, Texas Sweet or nothing at all.
Cooked, pickled and stuffed into a sub
Sweet onion the ingredient and "sweet onion" the menu word part ways fast. USDA's other records under that name are prepared foods, and they carry the calories of what surrounds the onion.
| Product | Per 100 g | US serving | Calories |
|---|---|---|---|
| Sweet onion chicken teriyaki sub, Subway | 155 kcal | 6-inch sub, 228 g | 353 kcal |
| Sweet onion chicken teriyaki sub, generic | 155 kcal | 6-inch sub, 228 g | 353 kcal |
| Sweet chowchow pickles with onion | 121 kcal | 1 cup, 245 g | 296 kcal |
The two sub rows are the same food logged twice — one branded, one generic — with identical values down to the 0.51 g of saturated fat, so pick either and don't count both. In both, sweet onion is a sauce, not a vegetable: the 353 calories are bread, chicken and glaze.
Chowchow is the sharper lesson. Same word "sweet," 121 calories per 100 g against 32, and 23.88 g of sugars per 100 g against 5.02. The sugar there was added by a canner. The sugar in a raw onion was not.
There is no USDA record for caramelized or stewed sweet onion, so we won't invent a number for the bowl in the photo. What we can say is arithmetic: caramelizing removes water and adds fat, so a pan of onion that started as 331 g and 106 calories ends up smaller, denser and heavier by whatever oil or butter went in — count the fat, not the onion.
Sweet without added sugar
Sweet onion earns the name honestly. Of the 7.55 g of carbohydrate in 100 g, 5.02 g are sugars — roughly two-thirds — and they are the onion's own fructose and glucose, concentrated by a low-sulfur growing soil that also makes these onions mild enough to eat raw. USDA reports no added sugars for this record. Total sugars have no Daily Value at all, which is why that cell reads as a dash on every label you'll ever see.
The row that surprises people is sodium: 8 mg per 100 g, 12 mg in a medium onion, 1% of the 2,300 mg DV. That's less than a fiftieth of a teaspoon of table salt. Compare it to the chowchow at 527 mg per 100 g, about 66 times as much, and you can see how much of the sodium in "onion" foods is the jar rather than the plant.
Fiber lands at 1.3 g per medium onion, 5% DV, and the Dietary Guidelines point most adults toward more vegetables than they eat. MyPlate counts a raw onion toward the vegetable group, and at 32 calories per 100 g it's one of the cheapest ways to buy volume and flavor at once. If you're watching sodium, raw sweet onion is the better pick over any jarred onion condiment, by a wide margin.
How does sweet onion compare?
| Food | Per 100 g | US serving | Calories |
|---|---|---|---|
| Sweet onion, raw | 32 kcal | one medium onion, 148 g | 47 kcal |
| Sweet chowchow pickles with onion | 121 kcal | 1 cup, 245 g | 296 kcal |
| Sweet onion chicken teriyaki sub, Subway | 155 kcal | 6-inch sub, 228 g | 353 kcal |
| Sweet onion chicken teriyaki sub, generic | 155 kcal | 6-inch sub, 228 g | 353 kcal |
Our take: the raw onion is the lightest of the four per gram by a long way — nearly four times lighter than the chowchow and almost five times lighter than either sub. For weight loss, raw or dry-cooked sweet onion is effectively free; a whole large one costs 106 calories and fills a plate. For satiety, the onion alone won't do it at 1.2 g of protein per medium bulb, so pair it with the protein rather than expecting it to carry a meal. And treat the word "sweet" on a menu as a warning label, not a description of the vegetable.
Most popular sweet onion brands in the United States
Ranked by how widely each product appears among foods sold in the United States, from the BodyPal food database of over 3.3 million products. Calories are the figures printed on each Nutrition Facts label, checked against USDA FoodData Central.
| Product | Calories (per 100 g) |
|---|---|
| REALSWEET Vidalia Sweet Onions | 41 cal |
| REALSWEET Sweet Onions | 30 cal |
Brand popularity: BodyPal food database. Nutrition: manufacturer labels / USDA FoodData Central.
Sweet onion FAQs
How many calories are in one sweet onion?
47 calories for a medium sweet onion of 148 g, the USDA labeling serving, at 32 calories per 100 g raw. A large onion weighs 331 g and comes to 106 calories. Half a medium onion is 24 calories, which is our arithmetic from the USDA 100 g figure.
How many calories in a Vidalia onion?
61 calories per 148 g medium onion on the REALSWEET Vidalia label, against 47 for the USDA raw sweet onion record. A second sweet onion bag from the same brand declares 44. Label numbers are rounded and packer-declared; we log the measured USDA value of 47 for any sweet onion.
How many carbs are in a sweet onion?
11.2 g of carbohydrate in a medium 148 g onion, which is 4% of the Daily Value, from 7.55 g per 100 g. Of that, 1.3 g is fiber and 7.4 g is total sugars. A whole large 331 g onion carries 25 g of carbohydrate by the same USDA figure.
Are sweet onions higher in sugar than yellow onions?
5.02 g of sugars per 100 g is what USDA measures in raw sweet onion, or 7.4 g in a medium bulb. We don't have a USDA yellow onion record in this page's data set, so we won't put a number on the gap. The taste difference owes as much to low sulfur as to sugar.
Do sweet onions have added sugar?
Zero added sugar: all 7.4 g of sugars in a medium 148 g onion are the plant's own fructose and glucose. USDA does not report added sugars for the raw sweet onion record, and a whole unprocessed onion has nothing added to it. Sweetened onion products differ: chowchow pickles hold 23.88 g of sugars per 100 g.
How many calories in half a sweet onion?
24 calories for half a medium onion, 74 g, scaled from the USDA 100 g figure of 32 rather than taken from a USDA serving. That half carries about 5.6 g of carbohydrate and 3.7 g of sugars. Half a large onion, 165 g, would be closer to 53 calories.
Are sweet onions good for weight loss?
At 32 calories per 100 g, yes, as a volume food. A whole large onion is 106 calories and fills a skillet. The catch is what goes in with it: a tablespoon of oil outweighs the entire onion, so dry-roast or water-saute it if the calorie count matters to you.
How much potassium is in a sweet onion?
176 mg in a medium 148 g onion, 4% of the 4,700 mg Daily Value, from 119 mg per 100 g. A whole large onion at 331 g supplies about 394 mg, or 8%. Sodium runs the other way at just 12 mg per medium onion, which is 1% of the DV.
Similar foods
- Broccoli — 55 cal per cup chopped
- Bamboo Shoots — 41 cal per cup sliced
- Bell Pepper — 31 cal per medium
- Bell Pepper — 24 cal green, 31 red
- Cabbage — 22 cal per cup chopped
- Cauliflower — 27 cal per cup chopped
Count it without the math
Point the camera at the cutting board and BodyPal counts the onion for you, medium or large.
