Carbs in Cornstarch: The Quick Answer
Cornstarch contains 90.4g of net carbs per 100g, calculated by subtracting 0.9g of dietary fiber from 91.3g of total carbohydrates. With 381 calories, 0.3g protein, and 0.1g fat per 100g, it is classified as High Carbs for carbohydrate content.
Net carbs — not total carbs — are what matter for keto and low-carb diets. Only net carbs raise blood sugar and affect insulin, which is why tracking them accurately is key to staying in ketosis. Use our Keto Macro Calculator to find your daily net carb limit based on your body and goals.
Is Cornstarch Keto Friendly?
Cornstarch is high in carbs with 90.4g net carbs per 100g. It is generally not suitable for strict keto (under 20g net carbs/day) but may fit into a broader low-carb diet depending on portion size and your daily limit.
Best Low-Carb Swaps for Cornstarch
Cornstarch is high in carbs. If you're eating low-carb or keto, these swaps deliver the same satisfaction with a fraction of the net carbs.
| Instead of | Try this | Why it helps |
|---|---|---|
| Cornstarch as a thickener (~91g net carbs per 100g) | Xanthan gum (use 1/4 the amount) | Powerful keto thickener — ~0g carbs, use ¼ tsp per cup of liquid |
| Cornstarch in gravy | Arrowroot powder (use 2/3 the amount) | ~9g net carbs per tbsp vs 7g for cornstarch — slightly better |
| Cornstarch in stir-fry sauce | A small amount of glucomannan powder (konjac) | ~0g net carbs, thickens instantly in hot liquid |
| Cornstarch as a coating for frying | Almond flour or pork rind crumbs | Crispier crust with zero starch carbs |
How Net Carbs Are Calculated
Net carbs are calculated by subtracting dietary fiber (and sugar alcohols, if present) from total carbohydrates: Net Carbs = Total Carbs − Fiber. For Cornstarch: 91.3g − 0.9g = 90.4g net carbs per 100g.
Dietary fiber is subtracted because it passes through the digestive system without being absorbed as glucose. It does not raise blood sugar or trigger an insulin response, making it irrelevant for carb counting on keto and low-carb diets.