Ingredient Weight Converter · vegetable
Chopped Onion: cups to grams
1 cup of chopped onion weighs 160 grams. Use the converter below for any other amount, or check the quick-reference table.
By Andrew Flores, Editor and publisher, Nathan Management. Last reviewed .
Density source: USDA FoodData Central, cross-checked against the King Arthur Baking weight chart. How these figures are derived and corrected is documented in our editorial standards.
Chopped Onion baseline: 1 cup = 160 g.
Common amounts
| Cups | Tablespoons | Grams | Ounces (weight) | Milliliters |
|---|---|---|---|---|
| 1/4 cup | 4.0 | 40 g | 1.41 oz | 59 mL |
| 1/3 cup | 5.3 | 53 g | 1.88 oz | 79 mL |
| 1/2 cup | 8.0 | 80 g | 2.82 oz | 118 mL |
| 2/3 cup | 10.7 | 107 g | 3.76 oz | 158 mL |
| 3/4 cup | 12.0 | 120 g | 4.23 oz | 177 mL |
| 1 cup | 16.0 | 160 g | 5.64 oz | 237 mL |
| 1.5 cups | 24.0 | 240 g | 8.47 oz | 355 mL |
| 2 cups | 32.0 | 320 g | 11.29 oz | 473 mL |
| 3 cups | 48.0 | 480 g | 16.93 oz | 710 mL |
| 4 cups | 64.0 | 640 g | 22.58 oz | 946 mL |
Spoon weights
Derived from the same 160 g per cup — a US tablespoon is 1/16 of a cup and a teaspoon is 1/48.
| Amount | Grams |
|---|---|
| 1 tablespoon | 10 g |
| 1 teaspoon | 3.3 g |
| 1/2 teaspoon | 1.7 g |
| 1/4 teaspoon | 0.83 g |
Chopped Onion at a glance
- Yield
- 1 medium onion (about 6 oz / 170 g whole) ≈ 1 cup chopped
- Sweating vs. browning
- Sweating is 5–8 minutes on medium-low until translucent; real caramelisation takes 35–45 minutes on medium-low, not the 10 minutes recipes usually claim
- Dice sizes
- fine 1/8 inch, medium 1/4 inch, large 1/2 inch — the same onion at different sizes cooks at very different rates
What a cup of chopped onion actually weighs
The published 160 g assumes one specific way of filling the cup. Here is what the same cup weighs under the other common handling methods and product forms, and how far off the recipe you end up.
| How it was measured | Grams per cup | vs. published | Why |
|---|---|---|---|
| Medium dice (about 1/4 inch) | 160 g | published figure | The published figure. Standard for soups, sauces, and sautés. |
| Finely diced (about 1/8 inch) | ~170 g | +6% | Smaller pieces pack tighter into the cup and cook much faster. |
| Sliced into rings or half-moons | ~115 g | -28% | Curved slices stack with large air gaps, so a cup holds far less onion. |
A tilde (~) marks a working estimate rather than a published figure — it varies with brand, grind, or how hard the cup was packed.
Why measuring chopped onion by cup goes wrong
Medium-diced yellow onion weighs about 160 grams per cup. A medium yellow onion (roughly the size of a tennis ball) yields about 1 cup chopped. Red onions are slightly denser; sweet onions like Vidalia are slightly less dense because they hold more water — which is also why they brown faster and store worse.
Practical tips for working with chopped onion
When a recipe says '1 medium onion, chopped,' it means about 1 cup. If you only have a giant onion, chop what you need and refrigerate the rest in a sealed container; it keeps three days before it starts to smell up the fridge. To cut down on tears, refrigerate the onion for 30 minutes before chopping — the cold slows the enzyme reaction that produces the airborne sulphur compound, and a sharp knife crushes fewer cells than a dull one.
Note from this ingredient's record: Medium dice. One medium yellow onion yields about 1 cup chopped.
Substitutions that work — and what they cost you
Shallots for onion
Ratio: About 3 medium shallots per medium onion
Trade-off: Milder, sweeter, and more delicate. They burn faster because of the higher sugar.
Onion powder for fresh
Ratio: 1 tablespoon onion powder ≈ 1 medium onion
Trade-off: Provides flavor but none of the bulk, moisture, or sweetness that comes from cooking a real onion down. Fine in a rub, wrong in a soup base.
When chopped onion ruins the recipe
| What you see | What went wrong | What to do |
|---|---|---|
| Onions burnt at the edges and stayed raw in the middle | Uneven dice — the small pieces cooked through before the large ones started. | Cut a uniform dice. Halve the onion root to tip, make horizontal and vertical cuts, then slice across. |
| 'Caramelised' onions came out pale and sharp after 10 minutes | Real caramelisation takes 35–45 minutes; most recipes badly understate it. | Medium-low heat, a pinch of salt to draw water out, and patience. Add a splash of water when the fond darkens and scrape it up. |
Storing chopped onion
Whole onions keep a month in a cool, dark, ventilated spot — never in a sealed bag and never next to potatoes, which give off moisture and gas that sprouts them. Cut onion: sealed container, refrigerated, three days.
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