Net carbs, explained
The number that actually matters on keto — and how to calculate it from any label.
What net carbs are
Net carbs are the carbohydrates your body actually digests and that raise blood sugar. The formula is simple: total carbohydrate minus fiber minus sugar alcohols. Fiber and most sugar alcohols pass through largely undigested, so they don't count toward your daily limit.
Example: a food with 20g total carbs, 8g fiber and 2g sugar alcohol has 10g net carbs.
Why low-carb eaters track net, not total
Tracking net carbs lets you eat more fiber-rich whole foods — leafy greens, avocado, nuts, berries — without blowing your budget, because their fiber is subtracted out. It's a more accurate picture of a food's real blood-sugar impact.
A caveat: not all sugar alcohols are inert. Maltitol raises blood sugar meaningfully, so many strict keto eaters only subtract half (or none) of maltitol grams.
Frequently asked
How do you calculate net carbs?+
Net carbs = total carbohydrate − fiber − sugar alcohols. For example, 20g carbs with 8g fiber and 2g sugar alcohol = 10g net carbs.
Should I count fiber as carbs on keto?+
No — fiber isn't digested into glucose, so it's subtracted. That's the whole point of tracking net carbs instead of total.
Are sugar alcohols always free?+
No. Erythritol and allulose have near-zero impact, but maltitol raises blood sugar. Read the type, not just the gram count.