Produce
Chopped Onion Conversion
Chopped Onion weighs 160g per US cup.
| Amount | Grams | Ounces |
|---|---|---|
| 1 cup | 160.0 g | 5.64 oz |
| 1/2 cup | 80.0 g | 2.82 oz |
| 1/4 cup | 40.0 g | 1.41 oz |
| 1 tbsp | 10.0 g | 0.35 oz |
| 1 tsp | 3.3 g | 0.12 oz |
| 100 g | 100.0 g | 3.53 oz |
Opens the converter already set to Chopped Onion — type any amount, including fractions like 1/2 or 1 1/4, and get grams, ounces, cups, tablespoons, teaspoons and millilitres at once.
The table above covers the amounts recipes ask for most often. For anything else — an odd fraction, an amount in ounces, a gram figure off a scale you want back in cups — the converter works in either direction and shows every unit at once.
Chopped onion's 160g per cup is one of the more variable figures in the produce category in practice, because "chopped" spans a real range — a coarse, large chop packs looser into a measuring cup than a fine dice, so this figure represents a medium, standard chop rather than an exact universal constant the way a fixed-composition ingredient like sugar has.
One medium onion yields roughly one cup of chopped onion, which is a genuinely useful rule of thumb beyond the precise gram figure — most recipes that call for "one onion, chopped" are implicitly assuming this same rough equivalence, which is part of why onion is one of the few produce items where a cup-based recipe instruction and a whole-item instruction are treated as roughly interchangeable in practice.
Onion's water content is high enough that its weight can shift noticeably between varieties (a sweet Vidalia onion vs. a standard yellow storage onion) and even by season, but not enough to meaningfully change this conversion for typical recipe purposes — the 160g figure is a reliable working average across common cooking onion varieties.
Chopped onion weighs about 160g per cup, though dice size shifts that somewhat — the bigger practical fact is how much water onions lose during a long, slow caramelization, where a large raw pile can collapse down to a small fraction of its starting volume as the sugars concentrate.
Yellow, white, and red onions differ meaningfully in sharpness and sweetness despite weighing about the same per cup chopped — yellow onions are the standard all-purpose cooking onion in most US recipes, while red onions are milder raw and more commonly used uncooked in salads.
Chilling an onion in the fridge for 15-30 minutes before cutting it, or slicing it under running water, are two common ways cooks cut down on the eye-watering sulfur compounds released when its cells rupture, without changing the flavor or texture of the finished dish.
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Frequently asked questions
Does the onion variety (yellow, white, red) change this conversion?
Not meaningfully — common cooking onion varieties are close enough in water content and density that this figure works as a reliable average across them; the differences between onion varieties matter more for flavor and sweetness than for weight.
How many cups of chopped onion does one medium onion yield?
Roughly one cup — a useful rule of thumb for recipes that specify "one onion" rather than a cup measurement, and part of why the two instructions are often treated as interchangeable in home cooking.
Does finely dicing versus roughly chopping change the weight in a cup?
It can shift it somewhat — a fine dice packs more densely with fewer air gaps than a rough chop, so a cup of finely diced onion may weigh slightly more than this figure, which represents a standard medium chop.
Does caramelizing onions change how much a cup weighs?
Dramatically — caramelized onions lose most of their water content during slow cooking, so a cup of caramelized onion weighs far less than a cup of raw chopped onion, even from the same starting quantity.
Does pearl onion or cocktail onion measure the same as standard chopped onion?
No — those are a different variety entirely, smaller and used mostly whole rather than chopped, so this page's chopped-cooking-onion figure isn't a meaningful reference for them.