Macro calculator

What are macros?

Macronutrients — protein, fat, and carbohydrates — are the three nutrients that provide calories. Tracking macros gives you more control over body composition than tracking calories alone, because the ratio of protein to fat to carbs directly affects muscle retention, satiety, hormone production, and energy levels. Two diets at identical calories can produce wildly different outcomes depending on the macro split.

• Protein — 4 kcal/g. Builds and repairs muscle. Has the highest thermic effect (20–30% burned in digestion) and the strongest satiety signal. Inadequate protein during a cut is the single biggest cause of muscle loss.
• Fat — 9 kcal/g. Essential for hormone production (testosterone, estrogen, cortisol) and absorption of vitamins A, D, E, and K. Dropping fat below 20% of calories for extended periods impairs hormonal health.
• Carbohydrates — 4 kcal/g. Primary fuel for high-intensity training and the nervous system. Spares protein from being burned for energy. Not technically essential — the body can produce glucose from protein and fat — but they dramatically improve training performance and recovery.

How to use this calculator

1. Enter your TDEE. If you don't know it, run the TDEE Calculator first. If you came here from that calculator, your TDEE is pre-filled automatically.
2. Enter your bodyweight in kilograms or pounds.
3. Enter your body fat percentage. Use the Body Fat Calculator if you don't have a number. A rough visual estimate (15% for most men, 25% for most women) is fine if you're ballparking.
4. Click Calculate Macros. Your protein, fat, and carb targets appear in grams per day along with a percentage breakdown.
5. Copy the targets into a tracking app (MyFitnessPal, Cronometer, MacroFactor) and hit them daily.

The formula

This calculator uses the lean-mass-based protein approach, which produces more accurate targets than the generic "30/30/40" ratios you'll see elsewhere:

Lean body mass  = weight × (1 − body fat %)

Protein (g)     = lean body mass (kg) × 2.2
Fat (g)         = (TDEE × 0.25) ÷ 9
Carbs (g)       = (TDEE − protein kcal − fat kcal) ÷ 4

Why 2.2 g/kg of lean mass?

A 2017 meta-analysis (Morton et al., British Journal of Sports Medicine) found that protein intake above ~1.6 g/kg of total bodyweight produces no additional muscle growth in most trainees. Setting protein against lean mass instead of total bodyweight avoids overfeeding protein to people with high body fat — a 100 kg person at 30% body fat needs protein for their 70 kg of lean mass, not all 100 kg. 2.2 g/kg lean mass usually works out to 1.6–1.9 g/kg of total bodyweight, landing in the proven effective range.

Why 25% of calories from fat?

This is a defensible floor for hormonal health. Studies on low-fat diets (Volek 1997, Hämäläinen 1984) show testosterone declines when fat drops below 15–20% of calories. 25% gives a safety margin while leaving room for carbs to fuel training. You can push fat higher (30–35%) if you prefer — the loss comes from carbs, which means lower training performance but equivalent body-composition results in most studies.

Why carbs fill the remainder

After protein and fat are set, calories are accounted for. Carbs get whatever's left. This preserves the two macros with the hardest physiological minimums (protein for muscle, fat for hormones) while letting carbs — the most flexible macro — flex around training.

How to interpret your result

These targets are for weight maintenance (eating at TDEE). The outputs tell you:

• Protein in grams/day — hit this daily within ±5 g. It is the non-negotiable number.
• Fat in grams/day — aim for this target; ±10% daily is fine.
• Carbs in grams/day — the most flexible. Time more of them around training for performance, less on rest days for hunger control.
• Percentage breakdown — a reference ratio; the gram targets are what you actually track.

What a sample day looks like

For a typical 80 kg male at 18% body fat with a 2,700 kcal TDEE:

• Lean mass: 65.6 kg → protein 144 g
• Fat: 75 g (675 kcal)
• Carbs: 334 g (remainder)

Three meals of 40–50 g protein plus a snack cover the protein target easily. Fat comes from cooking oils, nuts, fatty fish, and dairy. Carbs fill around training — oats and fruit pre-workout, rice and potatoes post-workout.

Hitting protein is the hard part

Most people underestimate how much protein 144 g actually is. Reference points:

• Chicken breast (150 g cooked): ~45 g protein
• Greek yogurt (200 g): ~20 g protein
• Whey shake (1 scoop): ~25 g protein
• Eggs (2 large): ~13 g protein

Build meals around a 30–50 g protein anchor, then add carbs and fat around it.

Common mistakes

• Counting protein from non-complete sources. Peanut butter lists "7 g protein" but it's low-quality and mostly fat. Track protein from meat, dairy, eggs, and whey first; treat plant sources as bonuses unless you're vegan (in which case aim 10–15% higher to offset the amino acid profile).
• Letting fat creep. Fat is calorie-dense and easy to under-log. One tablespoon of olive oil is 120 kcal.
• Fearing carbs. Low-carb is a valid preference but not required. At the same protein and calorie intake, carb level doesn't change fat loss or muscle gain in the average trainee.
• Recalculating weekly. These targets stay valid for 4–5 kg of bodyweight change. Recompute when you cross that threshold.

What to do next

• For fat loss: use the Cutting Macros Calculator to set a deficit with protein held at muscle-sparing levels.
• For muscle gain: use the Bulking Macros Calculator to set a surplus.
• To refine body fat %: use the Body Fat Calculator for a US Navy tape measurement.

Related tools

• TDEE Calculator — find your calorie baseline
• Cutting Macros Calculator — cut with a deficit
• Bulking Macros Calculator — bulk with a surplus
• Body Fat Calculator — measure body fat percentage

Lean body mass  = weight × (1 − body fat %)

Protein (g)     = lean body mass (kg) × 2.2
Fat (g)         = (TDEE × 0.25) ÷ 9
Carbs (g)       = (TDEE − protein kcal − fat kcal) ÷ 4