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How Much Is 1 Cup of Cornstarch in Grams?

1 cup of cornstarch equals 128.00 g. Cornstarch has a density of 128g per cup (128g per cup), which means it's relatively light compared to other common cooking ingredients. For comparison, 1 cup of honey would be 340 g.

1 cup of cornstarch
=
128.00g
Result using all cup standards info
128.00 g (US) 135.26 g (Metric Cup) 153.72 g (Imperial Cup)
1 cup of cornstarch is also
128.00

Formula and Step-by-Step

cups × 128g/cup = grams
  1. Start with 1 cup of cornstarch
  2. 1 cup of cornstarch = 128g
  3. 1 × 128 = 128g

The same formula works for any amount. Multiply (or divide) by the density, then convert units as needed.

Mental Math Shortcut

For 1 cup of cornstarch, just remember: 128g. Double it for 2 cups (256g), halve it for a half cup (64g).

Measuring Tip

For the most consistent results, weigh cornstarch on a kitchen scale. Volume measurements can vary by 20-30% depending on how the flour is scooped.

Cornstarch at Different Amounts

How cornstarch scales across common cups measurements. Your amount (1 cup) is highlighted.

0.25 cups32 g0.33 cups42.24 g0.5 cups64 g0.75 cups96 g1 cup128 g1.5 cups192 g2 cups256 g3 cups384 g

For reference, 1 cup of cornstarch (128g) is close in weight to a small apple (130g).

Other Amounts of Cornstarch

Cups US Grams Metric Cup Imperial Cup
0.25 cups 32.00 g 33.81 g 38.43 g
0.33 cups 42.24 g 44.63 g 50.73 g
0.5 cups 64.00 g 67.63 g 76.86 g
0.75 cups 96.00 g 101.44 g 115.29 g
1 cup 128.00 g 135.26 g 153.72 g
1.5 cups 192.00 g 202.88 g 230.58 g
2 cups 256.00 g 270.51 g 307.44 g
3 cups 384.00 g 405.77 g 461.17 g
4 cups 512.00 g 541.02 g 614.89 g
5 cups 640.00 g 676.28 g 768.61 g

Understanding the Units

What is a Cup?

A cup is a US customary unit of volume equal to 236.588 milliliters or 8 fluid ounces. It is the most common volume measurement in American recipes. One cup can be divided into 16 tablespoons or 48 teaspoons.

What is a Gram?

Grams are the preferred unit in professional kitchens and bakeries because they allow exact recipe scaling. To double a recipe, simply double the gram values. No need to worry about how tightly an ingredient is packed into a cup.

Frequently Asked Questions

About 128.00 g, based on cornstarch having a density of 128g per cup. The exact amount depends on how the ingredient is measured and the specific product.
Multiply the number of cups by 128 (grams per cup for cornstarch). For 1 cup: 1 × 128 = 128.00 g.
For the most accurate results, weigh cornstarch on a kitchen scale. If measuring by volume, sift or whisk first to break up clumps, then spoon into the measuring cup and level off. Do not scoop directly from the bag.
Yes, quite a bit. If you spoon the flour into your measuring cup and level it off, you will get about 128 grams per cup. If you dip directly into the flour bag and sweep level, the flour packs tighter and you can end up with 140.8 to 160 grams per cup instead. This conversion uses the spoon-and-level method, which is the standard most baking references follow.
Reverse the conversion: 128.00 g ÷ 128 = 1 cup. Or use the Grams to Cups converter.