How many calories in
yellow onion?
Yellow Onion comes in at 40 calories per 100g. A more substantial veg by calorie content.
Common serving sizes.
Calories scale with portion. Here's how a typical yellow onion serving translates in your tracker:
What 40 calories means.
Very low calorie — at 40 kcal per 100g, yellow onion adds volume to a meal without meaningfully denting a calorie deficit.
Yellow Onion vs. similar foods.
How yellow onion stacks up on calories and protein against foods people commonly compare it to:
Skip the lookup. Snap the plate.
Point your iPhone camera at yellow onion and Spotwell's AI estimates the portion and macros in a few seconds. Check it, adjust anything that looks off, and log it.
Download on theApp StoreQuick answers.
How many calories in yellow onion?
Yellow Onion has approximately 40 calories per 100g. A typical serving — 3 oz (85g) — comes in at 34 calories.
How much protein is in yellow onion?
1.1g of protein per 100g. That puts yellow onion at roughly 2.8g of protein per 100 calories — a useful lens when comparing to other vegetables sources.
How do I log yellow onion accurately?
The simplest method: weigh it on a kitchen scale, then enter grams in your tracker. With Spotwell, you can skip the scale — point the camera at the plate and the AI estimates the portion in a few seconds. Adjust the value if it looks off.
Is yellow onion good for weight loss?
It depends on your overall calorie target. Yellow Onion is naturally low-calorie at 40 kcal per 100g, so it's easy to fit into a deficit.