Convert Onion – Cups, Grams, Ounces & Milliliters

Need to convert onion between cups, grams, ounces, or milliliters? Unitzzz provides instant, precise conversions for raw, chopped onion using a working density of 0.67 g/ml. Perfect for soups, stews, stir-fries, salads, salsas, and roasting.

Common Onion Conversions

• 1 cup of chopped onion ≈ 160 grams
• 1 tablespoon of chopped onion ≈ 10 grams
• 100 grams of onion ≈ 0.63 cups
• 1 ml of chopped onion ≈ 0.67 grams
• 1 ounce of onion ≈ 28 grams
• 1 medium onion (about 150 g) ≈ just under 1 cup chopped

About Onion Density

Onions are mostly water but contain air pockets and fibrous layers, so they are lighter than many dense vegetables. For raw, chopped onion, a good average density is about 0.67 g/ml, meaning one cup weighs roughly 160 g. Finely minced onion packs more tightly and will weigh a bit more per cup; coarsely chopped onion will weigh less.

Cooking & Prep Tips

• For sautéing, measure onions by weight for consistent flavor and cooking time.
• Dice size affects cooking: smaller pieces cook faster and become sweeter.
• “1 medium onion” in recipes often corresponds to about 150–160 g chopped.
• Store cut onion in an airtight container in the fridge and use within a few days for best flavor.