Macro Calculator: Protein, Carbs & Fat

How macros are calculated

This calculator works in three steps. First it estimates your TDEE using the Mifflin-St Jeor BMR equation and an activity multiplier. Second it adjusts calories for your goal: −20% for fat loss, 0% for maintenance, +10% for a lean gain. Third it splits those calories into macronutrients using a protein-first method.

• Protein g = 2.2 × bodyweight(kg) (cut) or 1.8 (other)
• Fat g = 25% of calories ÷ 9
• Carbs g = (remaining calories) ÷ 4

Protein is set first because the research on muscle retention while dieting is unambiguous: 1.6–2.4 g/kg of bodyweight protects lean mass. Fat is set as a percentage of calories so it scales sensibly across body sizes. Carbohydrates absorb whatever's left, which is why heavier people training hard end up with carb numbers that look enormous compared to a small sedentary person on a cut.

How to use your macro targets

Treat the calorie number as a hard ceiling for fat loss and a soft target for maintenance. Treat protein as a floor, going over is fine. Carbs and fat are flexible: most people land within ±10 g of target and that's good enough. Track for two weeks, weigh yourself at the same time each morning, and average the readings over the whole week before reacting.

Build meals around protein first. A typical day looks like 3-4 meals each containing 30-50 g of protein from chicken, fish, eggs, dairy, lean beef, tofu, tempeh, legumes or a protein shake. Build carbs around training: more carbs on lifting days, fewer on rest days if you like, but weekly totals matter more than meal timing.

Worked examples

Example 1, 28F on a cut. 165 cm, 65 kg, light activity. TDEE ≈ 1,920 kcal. Cut target ≈ 1,540 kcal. Protein 143 g, fat 43 g, carbs 132 g. That's roughly 5 oz of chicken plus a serving of Greek yogurt and a scoop of whey, with the rest of the day built around oats, rice, fruit and vegetables.

Example 2, 30M on maintenance. 178 cm, 82 kg, moderate activity. TDEE ≈ 2,805 kcal. Protein 148 g, fat 78 g, carbs 351 g. Real food: 8 oz chicken or steak across the day, a few eggs, oats, rice or pasta, fruit, olive oil for cooking, snacks as wanted.

Example 3, 22M lean bulk. 175 cm, 75 kg, active. TDEE ≈ 3,234 kcal. Gain target 3,557 kcal. Protein 135 g, fat 99 g, carbs 477 g. Eat real food, train hard, accept that some of that weight will be body fat.

Common mistakes

• Going too low on fat. Below 20% of calories long-term hits hormones, mood and sleep.
• Treating carbs as the enemy. Carbs are training fuel. Cutting them slashes performance and adherence.
• Tracking only weekdays. Weekend overeating wipes out a weekday deficit. Track all seven days.
• Eyeballing portions of high-calorie foods. Oils, nut butters and cheese drift up fast, weigh them.
• Changing macros every week. Hold the line for 14 days minimum before reacting.

FAQ