Net carb calculator
Enter what your nutrition label says, choose how that label counts fiber, and see net carbs per serving plus the total you actually ate.
Result
Add your carbohydrate, fiber, and servings to see the estimate.
How we estimate net carbs
In US label mode we subtract fiber from total carbohydrate once: net carbs = total carbohydrate − fiber. If the label already excludes fiber, we keep the number as printed and never subtract it a second time. Any deduction you enter is applied after that base estimate, and both numbers stay visible.
Per-serving results are multiplied by the servings you ate to show total consumed. Values are rounded to one decimal place and calculated from unrounded inputs.
Worked examples
- US label
- 12 g total carbohydrate, 5 g fiber, 2 servings → 7 g per serving, 14 g consumed.
- Fiber already excluded
- 7 g carbohydrate, 5 g fiber, 2 servings → 7 g per serving, 14 g consumed — not 4 g.
- Fiber over total carbs
- 4 g carbohydrate with 6 g fiber is rejected with a field error instead of being clamped to zero.
What this tool can't tell you
- Net carbs are an estimate of what your body digests — not a measurement of ketosis.
- Label rounding rules differ by country, so treat small differences as noise.
- Sweetener handling varies by product; we only subtract what you confirm.
- Nothing here is personalised nutrition or medical advice.
Managing diabetes, taking insulin or glucose-lowering medication, pregnant or breastfeeding, or following a medically prescribed diet? Get professional guidance before making large changes to carbohydrate intake. See our medical disclaimer.
Keep reading
Net carb questions
Short answers to the label details people get stuck on.
Only when the label shows total carbohydrate that includes fiber, which is the US convention. Many European and Australian labels list carbohydrate with fiber already removed, so subtracting again would double-count it. Check the label before you pick a mode.
Not automatically. Sweeteners behave differently and there is no single universal adjustment. If you know from a label or your own plan how much is non-digestible, enter it as a deduction and we show both the base estimate and your adjusted one.
No. Net carbs are an estimate of digestible carbohydrate in one food. Whether you are in ketosis depends on your whole day, your body, activity, and other factors. This tool can't confirm ketosis.
Per-serving net carbs stay the same, but total consumed scales with how much you eat. Two servings of a 7 g per serving food gives 14 g consumed.
No. This calculator is not suitable for determining insulin or medication doses. Speak to your clinician for guidance on diabetes management or any medical diet.
