Macro Split Calculator
Break down your daily calorie target into grams of protein, carbohydrates, and fat based on your chosen macro percentages. Use this when starting a new diet plan, cutting, or bulking to hit precise nutrition targets.
About this calculator
Macronutrients provide all dietary calories: protein and carbohydrates each yield 4 calories per gram, while fat yields 9 calories per gram. Given a total daily calorie target and percentage allocations for each macro, grams are calculated as: Protein (g) = calories × (protein_percent / 100) / 4; Carbs (g) = calories × (carb_percent / 100) / 4; Fat (g) = calories × (fat_percent / 100) / 9. The three percentages must sum to 100%. The formula shown combines all three into a total-gram check: total = round((calories × protein% / 400) + (calories × carb% / 400) + (calories × fat% / 900)). Common splits include a balanced diet (30/40/30), keto (30/5/65), and high-protein cut (40/35/25). Adjusting these ratios lets you optimize for muscle gain, fat loss, or endurance performance.
How to use
Suppose your daily calorie goal is 2,000 calories with a 30% protein / 40% carb / 30% fat split. Protein: 2000 × 0.30 / 4 = 150 g. Carbs: 2000 × 0.40 / 4 = 200 g. Fat: 2000 × 0.30 / 9 = 66.7 g, rounded to 67 g. Verification: (150 × 4) + (200 × 4) + (67 × 9) = 600 + 800 + 603 = 2,003 calories (rounding adds ~3 cal). Your daily targets are 150 g protein, 200 g carbs, and 67 g fat.
Frequently asked questions
What is the best macro split for losing weight while preserving muscle?
A high-protein split of approximately 35–40% protein, 30–35% carbohydrates, and 25–30% fat is widely recommended for body recomposition during a caloric deficit. High protein intake (at least 1.6–2.2 g per kg of body weight) protects lean muscle mass while the deficit drives fat loss. Carbohydrates should remain sufficient to fuel training sessions, so very low-carb approaches may hinder performance for strength or HIIT athletes. Tracking actual gram targets rather than just percentages is the most practical approach.
Why do protein and carbs have 4 calories per gram but fat has 9?
The caloric density of a macronutrient reflects the energy released when it is oxidized (burned) in the body. Fat molecules contain long carbon-hydrogen chains that store significantly more chemical energy per unit mass than the shorter chains in carbohydrates or the nitrogen-containing amino acid structures of protein. This is why fat is the body's most efficient long-term energy storage form — one gram packs more than twice the energy of one gram of protein or carbohydrate. Fiber, technically a carbohydrate, yields only about 2 calories per gram because gut bacteria ferment rather than fully oxidize it.
How do I adjust my macro split for a ketogenic diet?
A standard ketogenic macro split is roughly 5% carbohydrates, 25–30% protein, and 65–70% fat. On a 2,000-calorie diet, this means approximately 25 g of carbs, 125–150 g of protein, and 144–156 g of fat per day. Keeping carbs below 20–50 g daily forces the liver to produce ketones from fat, shifting the body's primary fuel source from glucose to ketones. Electrolyte management (sodium, potassium, magnesium) is critical during the adaptation phase, as reduced insulin levels cause increased urinary excretion of these minerals.