Cornflour — Cups to Grams

1 cup of cornflour = 128 grams

1 cup of cornflour weighs approximately 128 grams. Use the converter below for custom amounts, or check the full conversion table.

Cornflour Converter

Amount

Result

128 g

Why Does Cornflour Weigh 128g Per Cup?

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Cornflour is very light — at 128g per cup versus water's 237g, it's about half as dense. The ultra-fine starch particles don't pack tightly, creating lots of air space. This lightness is why cornflour poofs up when you scoop it and why it's so effective as a thickener — a little goes a long way.

A cup of cornflour (128g) weighs almost the same as a cup of plain flour (125g), despite cornflour feeling lighter and silkier. Both are about half the weight of a cup of water. Compared to rice flour (160g per cup), cornflour is noticeably lighter. This similar weight to wheat flour is convenient for the "cake flour" substitution.

When Does Precision Matter for Cornflour?

Cornflour precision matters most when thickening sauces and puddings — too much creates a gluey, starchy texture; too little won't thicken properly. The general ratio is 1 tablespoon cornflour per cup of liquid for a medium-thick sauce. In baking, where cornflour replaces some flour for tenderness, precision matters less — a tablespoon more or less won't ruin the recipe. For coating foods before frying, precision doesn't matter.

How to Measure Cornflour Correctly

Cornflour should be measured by spooning it into the measuring cup and levelling it off — never scoop or pack. For precision, especially in small amounts, use a kitchen scale: 1 tablespoon = 8g. Always make a slurry (mix with cold liquid) before adding to hot liquids to prevent lumps. Sift if it has clumped. Cornflour is very light and can puff up when disturbed. For best results, use a digital kitchen scale for precision baking.

Understanding Cornflour Measurements

Cornflour (called cornstarch in the US) is pure starch extracted from corn kernels. One cup weighs approximately 128 grams. It's a fine, silky white powder used primarily as a thickening agent. Cornflour creates clear, glossy sauces (unlike flour, which makes opaque sauces) and is gluten-free. It has twice the thickening power of plain flour. Note: in some countries, "corn flour" (two words) means finely ground corn/maize flour — a completely different product. Learn more about how to measure flour correctly.

Common Uses in Baking & Cooking

Cornflour is the go-to thickener for sauces, gravies, puddings, and pie fillings — it creates a glossy, clear finish. In baking, replacing 2 tablespoons of flour per cup with cornflour creates a more tender crumb (this makes "cake flour"). It's essential in Chinese cooking for velveting meat and creating silky stir-fry sauces. It's also used to coat foods before frying for extra crispness. If you need a substitute, see our Cornflour substitution guide.

Storage and Handling Tips

Store cornflour in an airtight container in a cool, dry place. It keeps almost indefinitely if kept dry — moisture is its enemy and causes clumping. If it develops an off smell, absorbs odours, or clumps severely, replace it. Unlike flour, cornflour doesn't attract pantry pests as readily. Keep away from strong-smelling foods as it can absorb odours.

Need to convert cornflour to other units? Try our cups to grams converter or tablespoons to grams converter.

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Cornflour Conversion Table

Amount	Grams	Ounces
1 teaspoon	2.67g	0.09 oz
1 tablespoon	8g	0.28 oz
¼ cup	32g	1.13 oz
⅓ cup	42.7g	1.51 oz
½ cup	64g	2.26 oz
⅔ cup	85.3g	3.01 oz
¾ cup	96g	3.39 oz
1 cup	128g	4.52 oz
1½ cups	192g	6.77 oz
2 cups	256g	9.03 oz

Cornflour — US, Metric & UK Cup Conversions

Cup sizes vary by country. This table shows how much cornflour weighs when measured with US cups (most online recipes), metric cups (Australia, NZ, Canada), or UK/Imperial cups.

Amount	US Cup(236.6 ml)	Metric Cup(250 ml)	UK Cup(284 ml)
¼ cup	32g	33.8g	38.4g
⅓ cup	42.7g	45.1g	51.2g
½ cup	64g	67.6g	76.9g
⅔ cup	85.3g	90.2g	102g
¾ cup	96g	101g	115g
1 cup	128g	135g	154g
1½ cups	192g	203g	231g
2 cups	256g	271g	307g

Note: US cups (236.6 ml) are standard in most online recipes. Metric cups (250 ml, used in Australia, NZ, Canada) hold 5.7% more. UK/Imperial cups (284 ml) hold 20% more than US cups.

Measurement Note

Also called cornstarch.

Need a Substitute?

Out of cornflour? We've got 3 tested alternatives with exact ratios.

Arrowroot Powder(1:1)

Tapioca Starch(2 tbsp per 1 tbsp cornflour)

Plain Flour(2 tbsp per 1 tbsp cornflour)

See all alternatives for Cornflour →

Frequently Asked Questions

What is the difference between cornflour and cornstarch?▼

In the UK, Australia, and most of the world, "cornflour" means the pure white starch (what Americans call "cornstarch"). In the US, "corn flour" (two words) sometimes means finely ground whole corn (like very fine cornmeal). If a recipe calls for cornflour/cornstarch as a thickener, it means the white starch. If it calls for corn flour in cornbread, it means ground corn.

How do I use cornflour to thicken a sauce?▼

Always make a slurry first: mix cornflour with an equal amount of cold water until smooth. Then stir the slurry into your hot (not boiling) liquid. Bring to a simmer and cook for 1-2 minutes — cornflour needs heat to activate and lose its raw taste. The sauce will thicken as it heats. Use about 1 tablespoon cornflour per cup of liquid for medium thickness.

Can I substitute cornflour for plain flour as a thickener?▼

Yes, but use half as much cornflour — it has twice the thickening power of flour. So 1 tablespoon flour = ½ tablespoon cornflour. Cornflour creates clear, glossy sauces while flour creates opaque, matte sauces. Cornflour-thickened sauces don't hold up as well to reheating or freezing — they can become thin or spongy.

How many grams in 1 tablespoon of cornflour?▼

One tablespoon of cornflour weighs approximately 8 grams. One US cup weighs about 128 grams. In a metric cup (250ml), cornflour weighs about 135g. In a UK Imperial cup (284ml), it weighs about 153g. Cornflour is very light, so small volume measurements represent small weights.

Why did my cornflour sauce turn thin again?▼

Cornflour sauces can thin out if overcooked, over-stirred, or exposed to acid (like lemon juice or tomatoes). The starch molecules break down with excessive heat or agitation. To prevent this: don't boil vigorously after thickening, add acidic ingredients after thickening, and avoid stirring more than necessary. If reheating, do so gently. For acidic sauces, arrowroot is a better choice.

More Flours

Plain Flour125g/cup Self-Raising Flour125g/cup Bread Flour127g/cup Wholemeal Flour120g/cup Almond Flour96g/cup Coconut Flour128g/cup Rice Flour160g/cup Glutinous Rice Flour150g/cup Semolina167g/cup Buckwheat Flour120g/cup Rye Flour102g/cup

Related Converters

Cups to Grams Cups to Ounces Tablespoons to Grams Teaspoons to Grams

Values are approximate and can vary depending on how the ingredient is measured. For precision baking, we recommend using a digital kitchen scale.