The best cornstarch substitute depends on what you are cooking. For an everyday swap in gravies and sauces, use all-purpose flour at 2 tablespoons per 1 tablespoon of cornstarch, or arrowroot and potato starch at a straight 1:1. For a keto or low carb swap, use xanthan gum at just 1/4 to 1/2 teaspoon per tablespoon of cornstarch, since it adds zero net carbs and thickens on contact. Cornstarch itself carries about 7g net carbs per tablespoon, which is why keto cooks avoid it, but nearly every job it does can be handled by something already in your pantry.
Cornstarch substitutes at a glance
Net carbs below are per tablespoon and vary by brand, so always check the label. The swap ratio is measured against 1 tablespoon of cornstarch.
| Substitute | Swap ratio (per 1 tbsp cornstarch) | Net carbs per tbsp | Best for | Keto? |
|---|---|---|---|---|
| Xanthan gum | 1/4 to 1/2 tsp | ~0g | Sauces, soups, gravy, dressings | Yes |
| Glucomannan (konjac) | 1/4 to 1/2 tsp | ~0g | Glossy sauces, glazes, pie filling | Yes |
| Unflavored gelatin | 1 to 2 tsp bloomed | 0g | Set dishes, cold sauces, gravy | Yes |
| Ground flax | 1/2 tbsp | ~0g | Baked goods, rustic thickening | Yes |
| Chia (ground) | 1/2 tbsp | ~0-1g | Jams, puddings, thick fillings | Yes |
| Cream cheese / cream reduction | 1-2 tbsp | ~0.5g | Cream sauces, soups, gravy | Yes |
| Egg yolk | 1-2 yolks | ~0.5g | Custards, cream sauces, curds | Yes |
| Arrowroot | 1 to 1.5 tsp | ~7g | Clear sauces, fruit pies, glazes | No |
| Tapioca starch | 2 tbsp | ~7g | Glossy pie fillings, glazes | No |
| Potato starch | 1 tbsp | ~10g | Baking, soups, sauces | No |
| All-purpose flour | 2 tbsp | ~5g | Gravy, roux, opaque sauces | No |
| Rice flour | 1 tbsp | ~5g | Frying, crispy breading | No |
Why keto cooks skip cornstarch
Cornstarch is pure starch, which is a chain of glucose molecules. That means about 7g of net carbs in a single tablespoon, and recipes often call for several. A batch of stir-fry sauce or a fruit pie can add 20g or more of carbs from the thickener alone, enough to stall ketosis. It is also nutritionally empty, with no fiber, protein, or fat to slow digestion. The good news is that thickening power and carb count are not linked, so you can get the same body in a sauce from a zero-carb gum. For the bigger picture on which pantry staples fit, see our keto food list.
Keto-safe thickeners in detail
These are the swaps that add little or no net carbs, so they are the ones to learn if you are low carb.
Xanthan gum
Xanthan gum is the workhorse keto thickener. It is a fermented fiber that thickens liquid instantly and holds up under heat, so it works in gravies, pan sauces, soups, stir-fry sauces, and salad dressings. A little goes a very long way: start with 1/4 teaspoon per tablespoon of cornstarch called for, and add more only if the sauce is still thin. Too much turns a sauce slimy or gluey.
The one skill to master is avoiding clumps. Xanthan grabs water on contact, so if you dump it into hot liquid it seizes into slippery lumps that will not dissolve. Two techniques prevent this. First, whisk it in a pinch at a time while the sauce is moving, sprinkling from a few inches up so it disperses. Second, and more foolproof, blend it in: add the gum to the liquid in a blender or use an immersion blender, and it distributes perfectly. You can also premix it with a spoonful of oil or melted butter into a paste, then whisk that into the pan. Xanthan is also the binder keto bakers reach for, which we cover in the low carb flour substitutes guide.
Glucomannan (konjac) powder
Glucomannan is milled from the konjac root and is nearly pure soluble fiber, so like xanthan it has essentially zero net carbs. It thickens the same way and at the same tiny dose, roughly 1/4 to 1/2 teaspoon per tablespoon of cornstarch. Many cooks prefer it for clear applications like glazes, sweet-and-sour sauce, and fruit pie fillings because it produces a cleaner, more translucent finish than xanthan, which can look faintly matte. Use the same clump-avoidance moves: sprinkle and whisk, or blend. It is the same fiber used to make shirataki noodles, so it has a neutral taste.
Unflavored gelatin
Gelatin is pure protein with zero carbs and is ideal when you want a dish to set rather than just thicken. Bloom it first by sprinkling it over a little cold water and letting it swell for a few minutes, then stir it into the warm liquid until dissolved. It is excellent for cold sauces, glazes, panna cotta style fillings, and can add silky body to a gravy or a rich soup. The tradeoff is that gelatin firms up as it cools and can turn a sauce jiggly if you overdo it, so use 1 to 2 teaspoons per tablespoon of cornstarch and keep the dish warm when serving.
Reduction and dairy fat
Sometimes you do not need any added thickener at all. Simmering a sauce or stock uncovered evaporates water and concentrates it into something glossy and thick, which is how classic pan sauces are built. For cream sauces and soups, stirring in a spoonful of cream cheese, a splash of heavy cream, or a knob of butter thickens through fat and emulsion rather than starch, at well under 1g net carb. An egg yolk or two, tempered slowly into a warm (not boiling) sauce, thickens custards, curds, and cream sauces into a velvety texture the way it does in a proper carbonara or lemon curd. These methods are naturally keto and often taste richer than a starch-thickened version.
Ground flax and chia
Both seeds are mostly fiber, so they land near zero net carbs and thicken by forming a gel with liquid. Use about half a tablespoon of ground flax or chia per tablespoon of cornstarch. They shine in rustic, forgiving jobs: thickening a chili, a jam, a pudding, or a baked filling where a slightly textured, less glassy result is fine. They will not give you a clear, smooth sauce, and they add a mild nutty flavor, so save them for dishes where that fits.
Non-keto swaps that work (for the general cook)
If you are not counting carbs and just ran out of cornstarch, these behave the most like the real thing. They are not keto friendly, but they are what most kitchens reach for.
All-purpose flour
Flour is the swap almost everyone already has. It has about half the thickening power of cornstarch, so use 2 tablespoons of flour for every 1 tablespoon of cornstarch. The key is to avoid lumps: whisk the flour with an equal amount of cold water into a smooth slurry before stirring it into hot liquid, or cook it in fat first as a roux. Let the sauce simmer a few minutes to cook out the raw flour taste. Flour gives an opaque, matte finish rather than the clear shine of cornstarch, which is perfect for gravy but less ideal for a fruit glaze. At around 5g net carbs per tablespoon, it is off the keto table.
Arrowroot
Arrowroot powder is a gluten-free starch that is one of the closest matches to cornstarch, giving a clear, glossy result. Use 1 to 1.5 teaspoons per tablespoon of cornstarch. It shines in fruit pies, clear glazes, and Asian sauces. Two cautions: it can turn slimy if overheated or boiled hard, so add it near the end of cooking, and it breaks down when combined with dairy, so skip it for cream sauces. Despite being marketed as a health food, arrowroot has about 7g net carbs per tablespoon, essentially the same as cornstarch, so it is not a low carb swap.
Tapioca starch
Tapioca starch (also sold as tapioca flour) comes from the cassava root and gives the glossiest, most translucent finish of any swap, which is why it is a favorite for fruit pie fillings and glazes. Use roughly 2 tablespoons of tapioca per tablespoon of cornstarch. It thickens at a lower temperature than cornstarch and stands up to freezing, so it is a good choice for make-ahead pies. It carries about 7g net carbs per tablespoon.
Potato starch
Potato starch is a neutral, gluten-free starch that thickens at a 1:1 ratio with cornstarch and is especially good at keeping baked goods tender by softening proteins. It works in soups and sauces too, but add it late and avoid a hard boil, which can thin it back out. At roughly 10g net carbs per tablespoon it is the highest carb option here, so it is firmly non-keto.
Rice flour
Rice flour is the best non-keto pick for frying and crispy coatings, swapped 1:1. It fries up exceptionally light and shattery, which is why it is common in tempura and Korean fried chicken. It also thickens sauces without clouding them much. Brown and white rice flour both work. Expect about 5g net carbs per tablespoon.
Technique notes by use case
Glossy, clear sauces: cornstarch is prized for its shine. Among swaps, glucomannan, arrowroot, and tapioca give the clearest finish. Xanthan is close but slightly less transparent. Flour and gelatin will look opaque.
Gravy: flour (as a roux or slurry) is the traditional choice and gives the right body and color. For keto gravy, xanthan gum whisked into the pan drippings, or a cream and butter reduction, both work beautifully.
Frying and crispy coating: starches, not gums, create crunch. Rice flour, arrowroot, or potato starch dusted on before frying give the crispest crust. For keto, a thin dredge of finely milled almond flour or crushed pork rinds browns well, though it is more crumbly than glassy.
Pie filling: you want a thickener that sets clear and holds when sliced. Tapioca and arrowroot are the non-keto stars. For keto fruit fillings, glucomannan gives the cleanest set, with a little gelatin if you want it firmer.
What NOT to use
Baking powder and baking soda are leaveners, not thickeners. They make batters rise and will do nothing to set a sauce or pie, so they are not a substitute. This is one of the most common mix-ups, and the answer is simply no.
Almond flour and coconut flour thicken poorly on their own in a liquid sauce. They soak up moisture but turn grainy and gritty rather than smooth, so keep them for baking and breading, not for thickening a sauce.
Sweeteners and sugar alcohols do not thicken either. If a recipe needs both sweetening and thickening, handle them separately and see our keto sugar substitutes guide for the sweetener side.
The bottom line
There is no single best cornstarch substitute, only the best one for the dish in front of you. If you are cooking without regard to carbs, flour, arrowroot, tapioca, potato starch, and rice flour all do the job with minor ratio tweaks. If you are keto, xanthan gum and glucomannan replace cornstarch at a fraction of the amount with zero net carbs, gelatin sets cold and rich dishes, and a simple reduction or a spoonful of cream thickens without any powder at all. Keep a small bag of xanthan gum in the cupboard and you will rarely miss cornstarch again. For more pantry swaps, see our guides to low carb rice substitutes and low carb flour substitutes.
