Net Carbs vs Total Carbs: How to Count on Keto
Net carbs = total carbs − fibre − some sugar alcohols. The formula is simple; the exceptions are where people go wrong.
Short answer: Most keto plans count net carbs at around 20 g a day. Counting total carbs at a higher limit works too; choose one approach and use it consistently.
The formula
Net carbs = total carbohydrate − fibre − (eligible sugar alcohols)
Fibre is not digested into glucose in the small intestine, so subtracting it gives a better estimate of the carbohydrate that affects blood sugar. Our net carb calculator does the subtraction from any label.
Label differences by country
- US labels list total carbohydrate including fibre. Subtract fibre to get net carbs.
- UK, EU and Australian labels list carbohydrate excluding fibre. The "carbohydrate" figure is already close to net — do not subtract fibre again.
This is the single most common counting error among keto readers outside the US.
Sugar alcohols: not all equal
| Sweetener | Subtract fully? |
|---|---|
| Erythritol | Yes — very little is metabolised |
| Allulose | Yes in most counting approaches |
| Xylitol | Partly — some is absorbed |
| Maltitol | No — counts closer to sugar |
| Sorbitol | Partly |
"Keto" bars sweetened with maltitol (see our keto sweeteners guide) can show low net carbs on the wrapper while raising blood sugar noticeably.
Worked example
A US label shows 12 g total carbohydrate, 7 g fibre and 3 g erythritol per serving. Net carbs = 12 − 7 − 3 = 2 g. If that 3 g were maltitol instead, a fairer count would be about 12 − 7 − 1.5 = 3.5 g.
When to track total carbs instead
Some people with diabetes or those troubleshooting a stall track total carbs at 30–50 g. It is a simpler rule and removes the guesswork about fibre and sweeteners.
Frequently asked questions
Should I count net or total carbs on keto?
Most keto plans count net carbs at around 20 g a day. Counting total carbs at a higher limit works too; choose one approach and use it consistently.
Are net carbs the same in the UK?
UK and EU labels already exclude fibre from the carbohydrate figure, so that figure is effectively net carbs.
This guide is general information for healthy adults, not medical advice. See our medical disclaimer.