Macro Calculator
Split your daily calorie target into grams of protein, carbohydrates, and fat tuned to your goal — fat loss, muscle gain, maintenance, or keto. The output is the macro target sports-nutrition coaches and bodybuilders use to plan meals and track adherence with apps like MyFitnessPal or Cronometer.
About this calculator
Each macronutrient has a fixed calorie density: protein and carbohydrates each provide 4 kcal/g, fat provides 9 kcal/g, and (separately) alcohol provides 7 kcal/g. The calculator anchors macros to protein first, then fat, then fills the remainder with carbohydrates: Protein (g) = body weight (kg) × protein multiplier; Fat (g) = (total calories × fat fraction) ÷ 9; Carbs (g) = (total calories − protein × 4 − fat × 9) ÷ 4. The protein multiplier depends on goal and activity: 1.6–1.8 g/kg for general maintenance, 1.8–2.2 g/kg for muscle gain (bulking), and 2.0–2.4 g/kg during a cut (the higher figure preserves more lean mass in a calorie deficit). The fat fraction starts at ~0.25–0.30 of total calories for general use (the minimum needed for hormone production, fat-soluble vitamin absorption, and palatability), drops to ~0.20–0.25 in very low-fat protocols, and jumps to 0.65–0.80 on a strict ketogenic diet where carbs are pushed under ~20–50 g/day to induce nutritional ketosis. Carbs absorb whatever remains. This protein-first approach mirrors the consensus of the ISSN, ACSM, and most evidence-based sports-nutrition coaches: protein has the largest effect on body composition outcomes per gram, fat has a hard physiological minimum, and carbs are the flexible fuel that fills the calorie budget. Edge cases: at very low total calories combined with high protein and minimum fat, the carb remainder can drop to zero or go negative — the calculator floors it at 0 and signals the conflict by either reducing the protein target or flagging the budget. Keto-mode users should aim for a carb floor of ~20 g (not 0) to leave room for vegetables. Heavy alcohol consumption complicates everything — beer and wine calories displace either the fat or carb budget and are not included in standard macro models.
How to use
Example 1 — Lean bulk for a 75 kg lifter. Daily calories 2,800 kcal, goal muscle gain, body weight 75 kg, high training intensity (5+ days/week). Protein multiplier 2.0 g/kg → Protein = 75 × 2.0 = 150 g (600 kcal). Fat at 25% of calories → Fat = 2,800 × 0.25 ÷ 9 ≈ 78 g (700 kcal). Carbs = (2,800 − 600 − 700) ÷ 4 = 1,500 ÷ 4 = 375 g. ✓ Final targets: 150 g protein, 375 g carbs, 78 g fat, totalling 2,802 kcal — about 21% / 54% / 25% by calorie share, a typical hypertrophy split. Example 2 — Aggressive cut for an 80 kg lifter. Daily calories 2,000 kcal, goal fat loss, body weight 80 kg. Protein multiplier 2.4 g/kg → Protein = 80 × 2.4 = 192 g (768 kcal). Fat at 25% → Fat = 2,000 × 0.25 ÷ 9 ≈ 56 g (500 kcal). Carbs = (2,000 − 768 − 500) ÷ 4 = 732 ÷ 4 = 183 g. ✓ Final targets: 192 g protein, 183 g carbs, 56 g fat ≈ 2,000 kcal — about 38% / 37% / 25% by calorie share. The high protein protects muscle in the deficit; fat sits at the physiological floor; carbs flex to whatever total remains and concentrate around training sessions for the best performance.
Frequently asked questions
How much protein do I really need?
For sedentary adults, the RDA of 0.8 g/kg/day prevents nitrogen-balance loss but is well below the level that maximises muscle protein synthesis or supports an exercising person. The International Society of Sports Nutrition (ISSN) position stand recommends 1.4–2.0 g/kg/day for active individuals, with the upper end (1.6–2.2 g/kg) for those doing structured resistance training. During a calorie deficit, push toward 2.0–2.4 g/kg to preserve lean mass — this is the single most-replicated finding in body-composition research. Spreading protein across 3–5 meals of 25–40 g each maximises the muscle protein synthesis response throughout the day, since each meal triggers a synthesis spike that plateaus after about three hours regardless of dose. Above ~2.5 g/kg there is little additional benefit for muscle, though it remains safe for people with normal kidney function.
Is keto really better than a balanced macro split for fat loss?
Controlled studies that match calorie and protein intake between keto and balanced diets consistently find no significant difference in fat loss — what matters is the calorie deficit, not the macro composition. Keto works well for people who find it easier to control hunger when carbs are eliminated, and for those with specific metabolic conditions (refractory epilepsy, certain seizure disorders, some PCOS cases), but the metabolic advantage in body composition disappears when total calories and protein are equated. The two real downsides of strict keto: training performance for high-intensity work drops because glycolytic energy is limited, and long-term adherence is harder than a flexible diet for most people. If you enjoy carbs, a moderate-carb, high-protein split produces the same composition outcome with less restriction. The best macro split is one you can sustain for years, not weeks.
Why is fat capped at 25–30% of calories for most goals?
Below about 20–25% of calories from fat, several things degrade: testosterone production drops in men (multiple studies show a 10–15% decline at very low-fat intake even with adequate calories), absorption of fat-soluble vitamins (A, D, E, K) and carotenoids drops, food palatability tanks, and satiety often decreases. Above 35–40% of calories from fat in a non-keto setting, you start crowding out either protein or carbs without any compensating benefit. The 25–30% range is the sports-nutrition consensus default: enough to support hormones and vitamin absorption, not so much that it competes with protein needs or training-fuel carbs. Keto is the deliberate exception, pushing fat to 70%+ to switch the body into ketone metabolism — but that is a specific dietary strategy, not a general optimisation.
What are the most common mistakes people make with macro calculators?
Tracking calories obsessively but ignoring protein, then losing muscle along with fat in a deficit. Setting up macros and then failing to actually weigh food — eyeballed portions consistently underestimate intake by 20–40%. Picking keto or carnivore because they are trending without considering whether the restriction fits how you actually want to eat for the next five years. Over-trusting the third significant figure of macro targets — 156 g vs 162 g of protein on any given day makes essentially no difference; consistency week over week matters more than precision day to day. Forgetting that vegetables and fruits contain meaningful carbs and modest protein, which need to count toward totals. Eating "macro junk food" (low-fat ice cream, protein bars engineered to hit specific ratios) instead of whole foods, missing out on the fibre, micronutrients, and satiety those provide. And not adjusting macros as body weight changes — your protein target at 90 kg is not your protein target at 75 kg.
When should I not use this calculator?
Skip it if you have chronic kidney disease or moderately reduced renal function — high-protein targets (above ~1.0 g/kg) need medical clearance because protein loading increases the workload on the kidneys. Skip it during pregnancy and breastfeeding, when calorie needs add 300–500 kcal/day and specific micronutrient targets (iron, folate, choline, omega-3) matter more than macro ratios. Avoid it during eating-disorder recovery — strict macro tracking can entrench disordered patterns, and a registered dietitian with ED expertise should design the meal plan instead. Be cautious if you have diabetes on insulin: changing your carb intake without recalibrating insulin doses can cause hypoglycaemia. Children and adolescents should not be on adult macro plans without paediatric dietitian supervision. Finally, do not use a single-day macro hit as a measure of success — bodies respond to averages over weeks, and rigid adherence to a daily target produces worse adherence and worse outcomes than a flexible weekly average.