Net carbs are what count on keto. Take the total carbohydrate from the label and subtract the fibre and sugar alcohols your body does not absorb. More on the why in net carbs explained.
Total carbohydrate is everything on the label; net carbs are the part that reaches your bloodstream. Fibre passes through undigested, and most sugar alcohols do the same, so on keto the net figure is what decides whether you stay in ketosis. The one to watch is maltitol, a cheap sugar alcohol in many "low-carb" sweets that is partly absorbed and does raise blood sugar, which is why the tick box above only takes off half of it. A worked walk-through of each subtraction, with everyday examples, is in how to calculate net carbs, and the case for sometimes counting total carbs instead is in net carbs vs total carbs.
What are net carbs?
The carbohydrates your body digests into blood sugar: total carbohydrate minus fibre and most sugar alcohols.
Do you subtract maltitol?
Only half. Erythritol and allulose come off in full; maltitol is partly absorbed and spikes blood sugar, so the convention is to count half.
Should I track net or total carbs?
Net carbs for most people. If low-carb packaged products stall your progress, switch to the stricter total-carb count.
Net carbs = total carbohydrate − fibre − sugar alcohols. Fibre and most sugar alcohols (erythritol, allulose) pass through without raising blood sugar, so they come off in full. Maltitol is the exception: it is partly absorbed and does spike blood sugar, so the common convention is to subtract only half of it. On labels using the American convention, fibre is already outside the "total carbs" figure, so check whether your label is EU (fibre included) or US style. This is a guide, test your own response if you are unsure.