Cornstarch

Also known as corn flour, cornflour.

Pure starch extracted from corn. Primary use as a thickener and tenderiser.

Cornstarch is pure endosperm starch milled to a powder so fine it feels like silk between your fingers. It gelatinizes around 62-72C, swelling into a glossy, neutral-flavored thickener that sets clear rather than cloudy, which is why it underwrites everything from lemon meringue pie to the shattering crust on a fried chicken thigh.

Also Called

corn flourcornflour

Reviewed by the CupOrGram Editorial TeamSources: King Arthur Baking, USDA FoodData CentralMethodology

Properties

Density Index

0.54 g/cm3

1 Cup Weight

128g

Texture

Dry

Arrowroot Powder

Use 1:1

Very similar behaviour. Better for acid-based and frozen sauces.

Full substitute guide →All substitutes

Most-used links for Cornstarch

Conversion

Cornstarch cups to grams

1 cup = 128g

Conversion

Cornstarch grams to cups

Reverse the most common baking lookup.

Conversion

Cornstarch tablespoons to grams

Useful for small-batch adjustments and spoon measures.

Best Substitute

Arrowroot Powder

Use 1:1 for the closest starting point.

Where Cornstarch shines

Fruit pie fillings and puddings where you want transparency and gloss — cornstarch sets clear, so blueberries read blueberry, not chalky and veiled like with flour.
Frying coatings and dredges, alone or cut 50/50 with flour, for a thin, blistered, glass-like crust that stays crisp longer because starch holds less water than gluten.
Tenderizing cookies and shortbread by replacing 2-3 tablespoons of flour per cup — the dilution lowers gluten and yields a sandy, melt-on-the-tongue crumb.

What to watch

Boiling a cornstarch-thickened sauce past two minutes breaks the gel and the whole pot slacks back to liquid — bring to a bare simmer, then pull it.
Acid weakens starch bonds, so lemon curds and rhubarb fillings need either extra cornstarch (about 25% more) or the acid added after thickening sets up.
Lumps form when cold cornstarch hits hot liquid — always make a slurry with cold water first, or whisk it into sugar before it ever meets the pan.

Conversions

cups	grams
1/4 cups	32.0 grams
1/3 cups	42.0 grams
1/2 cups	64.0 grams
1 cups	128 grams
1.50 cups	192 grams
2 cups	256 grams
3 cups	384 grams
4 cups	512 grams

Figures use the US cup (236.6 ml).

Density: 0.54 g/ml

cups to grams grams to cups cups to ounces ounces to cups tablespoons to grams teaspoons to grams ounces to grams grams to ounces grams to tablespoons

Quick Convert

Ingredient-specific, density-based conversions for baking

AmountIngredientFromTo

Ingredient-specific · density-based

Cup size

Based on us cup (236.6 ml) · density data from baking references and our own measurements.

What the sources say cornstarch weighs

Published values, quoted at the exact measure each source lists. Sources round differently and assume different fill techniques — which is why they rarely agree to the gram.

Source	Listed measure	Weight
USDA FoodData Central	1 cup	128 g
King Arthur Baking	1/4 cup	28 g

CupOrGram standardizes on 128 g per cup (8 g per tablespoon, 3 g per teaspoon) and uses that single value on every page — how we reconcile the sources.

Recommended Tools & Pantry Picks for Cornstarch

Optional shopping references for bakers who want to compare tools and pantry options related to cornstarch.

Digital Kitchen Scale

Essential for cup-to-gram accuracy and repeatable bakes.

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Measuring Cup & Spoon Set

Useful for quick volume checks before converting to weight.

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Substitutions for Cornstarch

Arrowroot Powder

excellent

1:1

Very similar behaviour. Better for acid-based and frozen sauces.

Tapioca Starch

good

Use 2 tbsp tapioca per 1 tbsp cornstarch

Creates chewier, more elastic texture. Good for pie fillings.

All-Purpose Flour

good

Use 2 tbsp flour per 1 tbsp cornstarch

Half the thickening power. Creates opaque, less glossy results.

Potato Starch

good

1:1

Thickens at a lower temperature and gives a clear, glossy finish. Add near the end of cooking — prolonged boiling thins it out.

Large starch granules gel quickly but rupture under extended heat, releasing the liquid they trapped.

Rice Flour

good

Use 2 tbsp rice flour per 1 tbsp cornstarch

A reliable gluten-free thickener for gravies and stews and a crisp coating for frying. Finishes opaque rather than glossy.

Rice flour is about half starch by thickening power and contains protein, which clouds the sauce.

Xanthan Gum

moderate

¼ tsp per 1 tbsp cornstarch, whisked in gradually

Thickens without heat and holds up to acid and freezing. Very easy to overdo — too much turns sauces slimy.

A hydrocolloid that thickens by binding water directly rather than by gelatinising starch, so it needs no cooking.

Storage Tips

Cool, dry place. Indefinite shelf life if kept dry.

Baking Science

Thickens by gelatinizing starch granules when heated with liquid. Twice the thickening power of flour. Creates clear, glossy sauces.

Recipe Notes

Blueberry pie

Use 3 tablespoons cornstarch per 6 cups berries — flour leaves a starchy haze, tapioca leaves visible pearls, cornstarch sets the juice to a clean jewel-tone gloss. Toss with the sugar before the fruit so it disperses without clumping, and bake until you see thick bubbles in the center, not the edge.

Pastry cream

Two tablespoons cornstarch per cup of milk gives you a custard thick enough to pipe but still spoonable. Whisk it into the sugar and yolks dry, temper carefully, and once it bubbles in the center of the pan, count 60 seconds and pull — anything longer and the bonds start to slacken back to soup.

Korean fried chicken

A pure cornstarch dredge, double-fried at 160C then 190C, produces the lacquered, almost translucent shell that survives a glaze of gochujang and honey without going sodden. Wet the chicken with a thin buttermilk-cornstarch slurry first so the dry coat has something craggy to cling to.

Common Pitfalls

Switching brands without re-checking weight can change texture and bake time.
Using volume-only measurements for dense ingredients can overshoot recipe targets.
Expired leaveners can underperform even when measured correctly.

Brand Variance & Measuring Method

Baseline reference: 1 cup cornstarch = 128g. In real kitchens, a practical range is usually 120g-136g per cup (6% band).

Why this happens: fine powders and leaveners settle during storage, changing cup density.

Figures use the US cup (236.6 ml).

Common Questions

Can I swap cornstarch for flour as a thickener 1:1?

No — cornstarch has roughly twice the thickening power of flour, so use half as much. One tablespoon cornstarch equals about two tablespoons all-purpose flour for sauces and pie fillings.

Why did my cornstarch sauce turn thin again after cooling?

You almost certainly overcooked it. Cornstarch gels are fragile after about 2 minutes at a full boil or any contact with strong acid — the chains break and the sauce reliquefies as it sits.

Is cornstarch the same as corn flour?

In the US, no — corn flour here means finely ground whole corn, yellow and flavorful. In the UK and Australia, 'cornflour' is the same white, neutral starch Americans call cornstarch.

How many grams is 1 cup of cornstarch?

1 cup of cornstarch weighs 128 grams.

Explore Cornstarch Further

Cornstarch cups to grams Cornstarch grams to cups Cornstarch substitute guide Substitutes for Cakes Substitutes for Cookies Substitutes for Muffins & Quick Breads Full converter

Related Comparisons & Explainers

Cornstarch Substitute Cornstarch cups to grams All-Purpose Flour guide

Reference

See cornstarch in the full measurement table

Cup, tablespoon, and teaspoon weights for all ingredients, sourced and cross-checked.

Open reference →

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