You are halfway through a stir-fry sauce and the cornstarch box is empty. Or you are baking a fruit pie for the freezer. Cornstarch tends to break down and turn watery once thawed. Or you are on a low-carb diet and want to skip the starch altogether. Whatever the reason, cornstarch is easy to replace. Its one real job, thickening a liquid, can be handled by several pantry staples you probably already own.
What can you use instead of cornstarch?
The short answer: All-purpose flour, arrowroot powder, potato starch, tapioca starch, rice flour, ground flaxseed, xanthan gum, and guar gum all work as cornstarch substitutes. Grain starches like flour and rice flour need about double the amount to match cornstarch’s thickening power. Root starches like arrowroot, tapioca, and potato starch need about the same amount or a little more. They also hold up better in acidic or frozen dishes. Xanthan gum and guar gum need only a tiny fraction of the amount. They thicken through a completely different mechanism.
For full storage guidance on cornstarch itself, see our companion post: does cornstarch go bad. For a complete pantry reference, see our Food Storage Guide.
Cornstarch Substitutes at a Glance
All-purpose flour
2:1 ratio, everyday pantry swap
Arrowroot powder
~1.5:1 ratio, clear sauces and acidic dishes
Potato starch
1:1 ratio, neutral all-purpose swap
Tapioca starch
~2:1 ratio, pie fillings and freezer dishes
Rice flour
2:1 ratio, clear soups and broths
Ground flaxseed
1 tbsp plus 4 tbsp water per 2 tbsp cornstarch
Xanthan gum
1/4 tsp per 1 tbsp cornstarch, keto and low-carb
Guar gum
1/8 tsp per 1 tsp cornstarch, budget keto option
Key Takeaways
Cornstarch thickens through gelatinization, when its starch granules swell in hot liquid. Grain starches need more volume to match it. Root starches need about the same amount or a little more.
For a clear, glossy sauce or a dish headed for the freezer, arrowroot, tapioca, and potato starch all outperform cornstarch. They also hold up better against acid.
For everyday gravies and stews where a matte finish is fine, all-purpose flour is the simplest swap. Just use roughly double the amount.
For keto or low-carb cooking, xanthan gum and guar gum thicken powerfully in tiny amounts and add almost no carbohydrates.
Root starches lose their thickening power if overcooked. Add arrowroot, tapioca, and potato starch near the end of cooking rather than at the start.
Understanding What Cornstarch Actually Does
Before choosing a substitute, it helps to know how cornstarch actually thickens a dish. Cornstarch is pure starch pulled from the corn kernel’s endosperm, with the protein and fiber removed. When heated in liquid, its starch granules absorb water and swell. That process is called gelatinization, and it is what thickens a sauce, gravy, or pie filling.
Two Traits That Change With Each Substitute
The first trait is thickening power. Grain starches like wheat flour and rice flour
