One-Third Cup of Cornstarch in Grams

1/3 cup of cornstarch weighs 42.67g (1.51 oz, 80ml) according to USDA FoodData Central (1 cup cornstarch = 128g, spooned and leveled method). 1/3 cup = 0.3333 of a full cup (240ml). See the full conversion table below for all amounts from 1 tablespoon to 3 cups.

1/3 Cup
42.67g
1.51 oz
1/3 Cup → ml
80ml
0.533 g/ml density
1 cup reference
128g
USDA standard

Cornstarch Cup-to-Gram Conversion Table

Full range from 1 tablespoon to 3 cups. The highlighted row shows 1/3 cup.

AmountGrams
1 tbsp8g
2 tbsp16g
1/8 cup16g
1/4 cup32g
1/3 cupthis page42.67g
1/2 cup64g
2/3 cup85.33g
3/4 cup96g
1 cup128g
1 1/4 cups160g
1 1/2 cups192g
1 3/4 cups224g
2 cups256g
2 1/2 cups320g
3 cups384g

Source: USDA FoodData Central (FDC ID: 20027). 1 US cup = 240ml. Values use spooned-and-leveled method.

1/3 Cup of Different Ingredients — Weight Comparison

1/3 cup of different ingredients varies widely in weight because each has a different density. This matters when substituting ingredients in recipes.

Ingredient1/3 Cup (g)
Cocoa Powder (unsweetened)33.33g
Tapioca Flour (Starch)40g
Cornstarchcurrent42.67g
Arrowroot Powder42.67g

All values use USDA FoodData Central spooned-and-leveled method. Click any ingredient to see its full conversion table.

Measuring Cornstarch Accurately

Why weight matters: 1/3 cup of cornstarch can weigh anywhere from 36g to 51g depending on how you measure it. The USDA standard is 42.67g (spooned and leveled). Scooping directly from the container can add 10–20% extra weight, which affects recipe results — especially in baking.

About cornstarch density: Cornstarch (corn flour in UK) is a fine white powder. 1 cup = 128g. Used as a thickener for sauces and gravies. 1 tablespoon cornstarch = 2 tablespoons all-purpose flour as a thickener.

Spoon & Level
42.67g
USDA standard — most accurate for volume cups
Scooped (packed)
~49g
10–20% heavier — avoid for precision baking
Kitchen Scale
42.67g
Most reliable — eliminates technique variation

About 1/3 Cup as a Measurement

1/3 cup = 5 tablespoons + 1 teaspoon = 80ml. This unusual fraction appears in recipes that scale for 2 servings from a 3-serving base. It cannot be made from combining standard 1/4 and 1/8 cup measures without error.

One-third cup is common in yogurt parfait recipes, small-batch granola bars, and single-layer cake recipes scaled for 2 servings. It is exactly 80ml in metric volume.

Frequently Asked Questions

How many grams is 1/3 cup of cornstarch?

1/3 cup of cornstarch weighs 42.67 grams (1.51 oz, 80ml). Based on USDA FoodData Central: 1 cup cornstarch = 128g, so 1/3 cup = 128 × 0.333 = 42.67g.

Is 1/3 cup of cornstarch the same weight every time?

The weight can vary slightly depending on measuring technique. Spooned and leveled gives 42.67g. Scooped (packed) can be 10–20% heavier. Sifted gives a lighter weight. The USDA standard (spooned and leveled) of 42.67g is the most reliable baseline for recipes.

How do I accurately measure 1/3 cup of cornstarch?

For accuracy, use a kitchen scale and weigh 42.67g of cornstarch. If using measuring cups, spoon the cornstarch lightly into a 1/3 Cup measuring cup and level off the top with a straight edge. Avoid scooping directly from the container, which compacts the ingredient and adds extra weight.

How does 1/3 cup of cornstarch compare to other ingredients?

1/3 cup of different ingredients varies significantly: Cocoa Powder (unsweetened) = 33.33g, Tapioca Flour (Starch) = 40g, Cornstarch = 42.67g. This is because each ingredient has a different density.

Other Amounts for Cornstarch

Data source: USDA FoodData Central SR Legacy (FDC ID: 20027). View original USDA record

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