Macro Calculator

Macros—short for macronutrients—are the three nutrients your body needs in large amounts: protein (4 calories per gram), carbohydrates (4 cal/g), and fat (9 cal/g). Together they make up your total daily calories. While total calories determine whether you lose or gain weight, the macro split determines what kind of weight you gain or lose—muscle versus fat, energy levels, hunger, and workout performance all depend on it.

Step 1: Calculate your calorie target

Every macro plan starts with calories. We compute your BMR using the Mifflin-St Jeor equation, multiply by your activity factor to get TDEE, then apply a goal multiplier:

• Cut (fat loss): TDEE × 0.80 — a 20% deficit, ~1 lb/week loss for most people.
• Maintain: TDEE — body weight stays roughly constant.
• Lean bulk: TDEE × 1.10 — a 10% surplus, slow muscle gain with minimal fat.
• Bulk: TDEE × 1.15 — a 15% surplus, faster gain but more fat alongside muscle.

Aggressive 25–30% deficits accelerate fat loss but increase muscle loss and hunger. For most people, a 20% cut balances pace with sustainability. Lean bulks (+10%) minimize fat gain during muscle-building phases; aggressive bulks (+15–20%) gain muscle faster but require a cut afterward.

Step 2: Set protein first

Protein is non-negotiable—it's the only macro that builds and repairs muscle. Research consistently shows that 1.6 to 2.2 grams of protein per kilogram of body weight per day maximizes muscle protein synthesis and preserves muscle during cuts. Higher intakes (up to 2.6 g/kg) may help during aggressive cuts or for very lean individuals. Going below 1.6 g/kg on a cut virtually guarantees muscle loss. On a bulk, you can go slightly lower (1.6–1.8 g/kg) since the caloric surplus itself is muscle-sparing.

Protein also has the highest thermic effect of food (~25% of protein calories are burned digesting it, vs. ~5% for carbs and ~2% for fat) and is the most satiating macro—both helpful for cutting.

Step 3: Set fat second

Dietary fat supports hormone production (testosterone, estrogen, cortisol), cell membrane health, and absorption of fat-soluble vitamins (A, D, E, K). Drop fat too low and your hormones tank. The standard recommendation is 25% of total calories from fat, which works well across goals and activity levels. For very high-carb athletic diets, fat can drop to 20%; for low-carb approaches (keto, carnivore), fat may rise to 60–70%—but then carbs become the variable.

Step 4: Fill the rest with carbs

Whatever calories remain after protein and fat go to carbohydrates. Carbs are the body's preferred fuel for high-intensity exercise, support recovery, and are the easiest macro to scale up or down to hit your calorie target. Athletes, lifters, and active people thrive on higher carbs; sedentary individuals or those with insulin resistance often do better with lower carbs (and correspondingly higher fat). At 4 calories per gram, carbs offer the most flexibility without sacrificing protein or hormonal health.

Putting it together—an example

Take a 75 kg man with TDEE of 2,600 cal who wants to cut. His target is 2,600 × 0.80 = 2,080 cal/day. Setting protein at 2.0 g/kg gives 150g protein (600 cal). Setting fat at 25% of 2,080 = 520 cal = 58g fat. That leaves 2,080 − 600 − 520 = 960 cal for carbs, which is 240g carbs. Final macros: 150g protein / 240g carbs / 58g fat (29% / 46% / 25%). He'll lose ~1 lb per week while preserving muscle, provided he hits protein and trains hard.

Common macro tracking mistakes

Most failures come from underestimating intake (oil, sauces, handfuls of nuts), weighing food raw vs. cooked inconsistently, or abandoning ship after one bad day. Weigh food in grams, log everything for at least the first 2–3 weeks, hit protein first, and aim for weekly averages rather than daily perfection. Re-calculate your macros every 5–10 lbs of weight change—your TDEE shifts as your body composition does.