Carb cycling calculator
Carb fasting keeps carbohydrate near zero on fast days and normal on the rest. This estimates your daily energy need, then gives a starting carbohydrate range for normal days. A place to begin, not a rule.
Fill in the fields above to see your estimate.
A starting estimate, not medical or nutrition advice. Energy needs vary from person to person. Adjust by how you feel and respond, and talk to a clinician or dietitian if you have a medical condition.
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How it is calculated
Resting energy uses the Mifflin-St Jeor equation, the standard dietitian estimate of resting metabolic rate:
- Men: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
- Women: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
That number is multiplied by an activity factor for your daily need. A moderate share of those calories (÷ 4 kcal per gram) becomes the normal-day carbohydrate range. Fast days stay near zero by design.
Worked example: a lightly active man, 82 kg, 178 cm, age 35. Resting energy about 1,763 kcal, daily need about 2,424 kcal. At 35 to 45 percent carbohydrate, that is roughly 210 to 275 g on a normal day, and near zero on a fast day.
What to do with the number
Treat it as a starting point and adjust by how you feel and respond. The exact gram count matters far less than the pattern: fast days and normal days. For meal ideas, see the carb cycling meal plan. To lay out your week, use the fast-day planner.
References
The free book
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