What this calculator does
Net carbs works out carbohydrate grams likely to affect blood sugar, after subtracting fibre and sugar alcohols. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaNet carbs = Total carbohydrate − Fibre − (Sugar alcohols × 0.5)
The inputs explained
| Field | What to enter |
|---|---|
| Total carbohydrate (g) | A number, measured in g. Starts at 30. |
| Fibre (g) | A number, measured in g. Starts at 5. |
| Sugar alcohols (g) | A number, measured in g. Starts at 0. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with total carbohydrate
Every other input is held at the calculator’s starting values while total carbohydrate varies. Select any row to load that scenario into the calculator.
How the answer changes with total carbohydrate
| Total carbohydrate (g) | Net carbs | Total carbohydrate | Note |
|---|---|---|---|
| 15 | 10.0 g | 15.0 g | A widely used low-carb/keto convention, not an official regulatory figure: some sugar alcohols (e.g. erythritol) are sometimes excluded entirely instead of halved. |
| 22.5 | 17.5 g | 22.5 g | A widely used low-carb/keto convention, not an official regulatory figure: some sugar alcohols (e.g. erythritol) are sometimes excluded entirely instead of halved. |
| 30 | 25.0 g | 30.0 g | A widely used low-carb/keto convention, not an official regulatory figure: some sugar alcohols (e.g. erythritol) are sometimes excluded entirely instead of halved. |
| 45 | 40.0 g | 45.0 g | A widely used low-carb/keto convention, not an official regulatory figure: some sugar alcohols (e.g. erythritol) are sometimes excluded entirely instead of halved. |
| 60 | 55.0 g | 60.0 g | A widely used low-carb/keto convention, not an official regulatory figure: some sugar alcohols (e.g. erythritol) are sometimes excluded entirely instead of halved. |
| 90 | 85.0 g | 90.0 g | A widely used low-carb/keto convention, not an official regulatory figure: some sugar alcohols (e.g. erythritol) are sometimes excluded entirely instead of halved. |