A fine, nearly pure starch used to thicken fillings, sauces, custards, and tender baked goods.
1 cup = 128g
Cornstarch
Measured
spooned lightly and leveled
Category
Powder
Cornstarch is a nearly pure starch used to thicken sauces, custards, pie fillings, and puddings, or to soften the structure of some cakes and cookies. It must be dispersed before heating so the granules hydrate evenly instead of forming lumps.
Its very fine particles settle quickly, so keep the container dry, break up lumps, spoon lightly, and level without tapping. Under the adopted state, 1 US cup is about 128 grams; weighing is especially useful for large batches.
Data last verified: August 5, 2026
Small starch particles settle quickly, and tapping lets more powder occupy the same cup volume.
Moisture-driven lumps leave uneven air spaces unless they are broken up before measuring.
spooned lightly and leveled
Cornstarch
128g per cup
Dry, unsifted, with lumps broken up before measuring.
Corn flour
In the UK this often means cornstarch; elsewhere it may mean finely milled whole corn.
These limited reference values are derived from the canonical cup weight. Use the converter for any other amount.
| Cups | Grams |
|---|---|
| ¼ cup | 32g |
| ⅓ cup | 42.7g |
| ½ cup | 64g |
| 1 cup | 128g |
Tapioca starch
Thickens with a glossier finish and a different weight per cup.
The adopted reference is about 128 grams per US cup for dry cornstarch with lumps broken up.
Tapping settles the fine particles and packs more starch into the same volume, making the cup heavier.
Its starch granules absorb water and swell when heated. Mixing it with a cool liquid before heating helps prevent dry lumps in sauces, custards, and fillings.
Keep it airtight and dry. Moisture causes persistent clumps and can make both dispensing and volume measurement unreliable.