Cups to Grams: Cornstarch
1 cup of cornstarch is about 128 grams. Enter any amount to convert it.
How many grams are in a cup of cornstarch?
One US cup of cornstarch weighs about 128 grams (4.5 ounces). Half a cup is about 64 g, and one tablespoon is about 8.0 g.
Cornstarch packs lightly and is usually measured by the tablespoon (about 8 g each). Level the spoon rather than heaping it.
Cornstarch conversion chart
| Volume | Grams | Ounces |
|---|---|---|
| ¼ cup | 32 g | 1.1 oz |
| ⅓ cup | 43 g | 1.5 oz |
| ½ cup | 64 g | 2.3 oz |
| ⅔ cup | 85 g | 3.0 oz |
| ¾ cup | 96 g | 3.4 oz |
| 1 cup | 128 g | 4.5 oz |
| 1½ cups | 192 g | 6.8 oz |
| 2 cups | 256 g | 9.0 oz |
| 1 tablespoon | 8.0 g | 0.3 oz |
| 1 teaspoon | 2.7 g | 0.1 oz |
Using cornstarch to thicken
Cornstarch is a pure starch, so a little goes a long way. It is usually measured by the tablespoon, and a level tablespoon is about 8 g. Level the spoon with a knife instead of heaping it, because a few extra grams makes a sauce gluey.
As a rule of thumb, 1 tablespoon (8 g) of cornstarch thickens 1 cup of liquid to a light sauce, and 2 tablespoons gives a pudding-like consistency. Always mix the cornstarch with a little cold water into a smooth slurry before it goes into hot liquid, or it forms lumps. Then bring the sauce to a gentle boil for about a minute: cornstarch does not reach full thickness or lose its raw starch taste until it has simmered briefly.
Substitutions and things that go wrong
Cornstarch has roughly twice the thickening power of flour, so 1 tablespoon of cornstarch can replace 2 tablespoons of flour. Arrowroot and potato starch swap one for one with cornstarch, though arrowroot turns slimy with dairy and potato starch should not be boiled for long.
Cornstarch-thickened sauces do not freeze well, because they weep when thawed. Acidic ingredients such as lemon juice or vinegar can also thin them, so add acid at the end. Cornstarch also shows up in baking: a spoonful replaces some of the flour in shortbread and cookies for a more tender texture. In the UK it is sold as cornflour.
Frequently asked questions
How many cups is 100 grams of cornstarch?
100 g of cornstarch is about 0.78 cups.
How many grams is a tablespoon of cornstarch?
About 8.0 g, based on 128 g per cup and 16 tablespoons per cup.
How much cornstarch should I use per cup of liquid?
About 1 tablespoon for a light sauce and 2 tablespoons for a thick, pudding-like one.
Is cornstarch the same as cornflour?
In the UK and Australia, cornflour is the same product as American cornstarch. In the US, "corn flour" is a different product made from ground whole corn.
How many cups is a pound of cornstarch?
A pound (454 g) is about 3½ cups.