How Many Grams in a Cup of Cornstarch?
1 cup = 128g · Tablespoon and teaspoon counts are US volume measures (16 tbsp and 48 tsp per cup). Spoon weights use this ingredient's density.
Quick values
- Cups
- 1
- Tablespoons
- 16
- Teaspoons
- 48
- Grams per tbsp
- 8g
- Grams per tsp
- 2.666667g
- Grams
- 128
- Ounces
- 4.515071
- Pounds
- 0.282192
Cornstarch cups to grams conversion table
| Cups | Tablespoons | Teaspoons | Grams | Ounces |
|---|---|---|---|---|
| 1/4 | 4 | 12 | 32g | 1.128768 |
| 1/3 | 5.333333 | 16 | 42.666667g | 1.505024 |
| 1/2 | 8 | 24 | 64g | 2.257535 |
| 2/3 | 10.666667 | 32 | 85.333333g | 3.010047 |
| 3/4 | 12 | 36 | 96g | 3.386303 |
| 1 | 16 | 48 | 128g | 4.515071 |
| 1.5 | 24 | 72 | 192g | 6.772606 |
| 2 | 32 | 96 | 256g | 9.030142 |
Each US tablespoon ≈ 8g · Each US teaspoon ≈ 2.666667g
About Cornstarch measurements
Cornstarch is a fine starch from corn used to thicken sauces, pie fillings, and shortbread, and to soften cake flour blends. One US cup weighs approximately 128 grams—denser than flour because starch particles pack tightly when settled. Arrowroot and potato starch differ slightly but often use similar cup conversions in home cooking.
Spoon cornstarch into a measuring cup without packing or tap the cup, which compacts starch dramatically. For slurry thickening, weighing small amounts on a scale beats estimating tablespoons. Sift before adding to dry cake mixes to prevent lumps that survive mixing.
Mistakes include using cornstarch interchangeably with flour for thickening—cornstarch has twice the thickening power by weight. Adding dry cornstarch directly to hot liquids clumps; always slurry with cold water first. Confusing cornstarch with cornmeal, which is coarse and far heavier per cup, ruins recipes.
Store cornstarch sealed indefinitely in a dry pantry; moisture causes clumping. Substitute arrowroot or tapioca starch at equal weight with minor texture differences in fillings. For cake flour DIY blends, two tablespoons cornstarch per cup of all-purpose flour replaces commercial cake flour approximately.
Cornstarch at 128 grams per cup thickens gravies and fruit pie fillings with roughly twice the power of flour by weight, so cup conversions must pair with thickening knowledge—not just math. Slurry recipes listing tablespoons convert cleanly when you know one cup equals 16 tablespoons at 8 grams each approximately. For stir-fry velveting, cornstarch weight affects marinade cling on meat surfaces. Arrowroot and potato starch substitute at similar weights but break down differently under prolonged heat or freezing, so conversion alone does not guarantee identical texture in make-ahead dishes.
When thickening one cup of liquid, start with about 8 grams cornstarch (roughly one tablespoon) slurried in cold water; knowing 128 grams fills a cup helps scale this rule for larger gravy batches.
Frequently asked questions
One US cup of cornstarch equals 128 grams when spooned and leveled without tapping the cup.
Spoon gently into a dry cup and level, or weigh 128g. Never scoop compacted starch from a humid container.
Arrowroot, potato starch, or tapioca starch substitute at equal weight. All-purpose flour needs double the amount to thicken equally.
Keep sealed in a dry pantry indefinitely. Break clumps by sifting. Protect from moisture and insects.