About the Carb Cycling Calculator
Carb cycling means eating more carbohydrate on hard training days and less on rest days, while keeping protein steady and total weekly calories on target. This calculator builds that plan for you: choose how many high, moderate and low carb days you want, and it works out calories and grams of protein, carbs and fat for each day type.
It suits lifters and athletes who want fuel for heavy sessions during a fat-loss phase, and anyone who finds it easier to diet with a few lower-carb days. Start from your maintenance calories (TDEE), choose a goal adjustment, and set carbs per kilogram of body weight for each day type — the defaults of 4, 2.5 and 1 g/kg are common starting points.
Protein is held constant every day. Fat fills the remaining calories and moves opposite to carbs, offsetting half of each day’s carb swing, so high days are higher-calorie/lower-fat and low days are lower-calorie/higher-fat while the weekly total stays on target. Evidence that carb cycling beats a steady diet with the same weekly calories is limited — its main benefit is matching fuel to training and adherence.
With the default inputs, the average daily calories is 2,125 kcal. Change any value above to recalculate instantly.
How to use the carb cycling calculator
- 1Enter your maintenance calories (TDEE) and choose a goal.
- 2Enter your body weight and daily protein target in g/kg.
- 3Choose how many high and moderate carb days you want; the rest become low days.
- 4Adjust carbs per kg for each day type if you like.
- 5Match high-carb days to your hardest training and follow the per-day macros.
Formula and method
The weekly calorie budget is your maintenance calories adjusted for your goal, times seven. Protein is set in grams per kilogram and eaten every day. Carbs for each day type are grams per kilogram of body weight times your weight.
C̄ is the average daily carbohydrate across the week. On an average day, fat fills whatever calories remain after protein and carbs. On each day type, fat is then moved in the opposite direction to half of that day’s carb difference from average, so a high day that adds 400 kcal of carbs removes 200 kcal of fat. Because the carb differences sum to zero over the week, the seven-day average still equals your target, unless fat would fall below zero — then it is set to zero and a warning appears.
- TDEE
- Total daily energy expenditure (maintenance calories)
- goal%
- Calorie adjustment for fat loss (negative) or gain (positive)
- g/kg
- Grams of carbohydrate (or protein) per kilogram of body weight
Worked examples
180 lb lifter cutting at −15% (2 high, 2 moderate, 3 low)
At 180 lb (81.6 kg) the budget averages 2,500 × 0.85 = 2,125 kcal a day. Protein is 163 g daily; carbs are 327 g on high days, 204 g on moderate and 82 g on low days. Fat offsets half the carb swing, giving about 49 g, 77 g and 104 g of fat and roughly 2,405, 2,160 and 1,915 kcal on the three day types.
70 kg athlete maintaining, 3 high and 4 low days
Average carbs are (3 × 350 + 4 × 140) ÷ 7 = 230 g (920 kcal). After 504 kcal of protein, an average day has 1,376 kcal for fat. High days carry 480 kcal more carbs than average, so fat drops by 240 kcal to about 126 g (3,040 kcal total); low days carry 360 kcal less, so fat rises to about 173 g (2,620 kcal).
Frequently asked questions
What is carb cycling?+
Carb cycling alternates higher- and lower-carbohydrate days through the week, usually eating more carbs on intense training days and fewer on rest days, while keeping protein steady and weekly calories on target.
Does carb cycling help you lose more fat?+
Fat loss is driven by the weekly calorie deficit. Studies have not shown carb cycling to burn more fat than a steady diet with the same calories and protein, but some people find it easier to stick to and better for training performance.
How many high carb days should I have?+
A common setup is 2–3 high days on your hardest training days, 2 moderate days and 2–3 low days on rest days. More training volume usually warrants more high days.
How many carbs on low carb days?+
Low days are typically around 0.5–1.5 g of carbs per kg of body weight — often 50–120 g for most adults — with fat raised to keep calories reasonable. Very low days under 50 g may reduce training quality.
Should fat change with carbs?+
Yes. Most carb cycling plans lower fat on high-carb days and raise it on low-carb days so daily calories do not swing too far. This calculator offsets half of each day’s carb change with fat in the opposite direction.
This tool gives general estimates and is not medical advice. Talk to a doctor or qualified professional about your health, diet or training.