How to Calculate Your Daily Macros for Weight Loss or Muscle Gain
Macros — protein, carbs, and fat — are the three levers you control to change your body composition. Here's the exact math to find your daily targets.
Counting calories works. Counting macros works better — it tells you not just how much to eat, but what to eat to hit your specific goal, whether that's fat loss, muscle gain, or both.
This guide covers the two-step process: (1) find your Total Daily Energy Expenditure (TDEE), then (2) split those calories into protein, carbs, and fat based on your goal.
Step 1: Calculate Your TDEE
Your TDEE is the total calories your body burns in a day, including activity. It starts with your Basal Metabolic Rate (BMR) — the calories you'd burn doing nothing — then multiplied by your activity level.
BMR: Mifflin-St Jeor Equation
The most accurate widely-used formula:
Example: 30-year-old man, 175 lbs (79.5 kg), 5'10" (178 cm):
BMR = 10(79.5) + 6.25(178) − 5(30) + 5 = 795 + 1112.5 − 150 + 5 = 1,762 calories
TDEE: Multiply by Activity Multiplier
| Activity Level | Description | Multiplier |
|---|---|---|
| Sedentary | Desk job, little/no exercise | 1.2 |
| Lightly Active | 1–3 days/week exercise | 1.375 |
| Moderately Active | 3–5 days/week exercise | 1.55 |
| Very Active | Hard exercise 6–7 days/week | 1.725 |
| Extra Active | Athlete or physical job | 1.9 |
Continuing our example, moderately active (3–5 days/week): TDEE = 1,762 × 1.55 = 2,731 calories/day
Step 2: Adjust for Your Goal
With your TDEE in hand, add or subtract calories based on what you're trying to do:
- Lose fat (aggressive): TDEE − 500 cal/day → ~1 lb loss/week
- Lose fat (moderate/sustainable): TDEE − 250 cal/day → ~0.5 lb/week
- Maintain weight: Eat at TDEE
- Lean bulk (minimize fat gain): TDEE + 200–300 cal/day
- Bulk: TDEE + 400–500 cal/day
Our example person wanting to lose fat moderately: 2,731 − 250 = 2,481 calories/day target
Never go below 1,200 calories/day (women) or 1,500/day (men) without medical supervision — below these thresholds, muscle loss accelerates and metabolism slows.
Step 3: Split Into Macros
Here are the most common macro splits and when to use each:
| Split | Protein | Carbs | Fat | Best For |
|---|---|---|---|---|
| Balanced | 30% | 40% | 30% | General fitness, maintenance |
| High Protein | 40% | 35% | 25% | Muscle gain, body recomp |
| Low Carb | 40% | 20% | 40% | Fat loss, insulin sensitivity |
| Keto | 30% | 5% | 65% | Ketosis, some epilepsy management |
| High Carb | 25% | 55% | 20% | Endurance athletes, marathon runners |
Converting Percentages to Grams
Calories per gram: Protein = 4 cal/g · Carbs = 4 cal/g · Fat = 9 cal/g
Example (2,481 calories, balanced 30/40/30 split):
- Protein: 2,481 × 0.30 ÷ 4 = 186g/day
- Carbs: 2,481 × 0.40 ÷ 4 = 248g/day
- Fat: 2,481 × 0.30 ÷ 9 = 83g/day
Protein: The Most Important Macro
Protein is non-negotiable regardless of your goal. It preserves muscle during fat loss and builds muscle during a surplus. General guidelines:
- Minimum (general fitness): 0.7g per pound of bodyweight
- Fat loss / body recomp: 0.8–1.0g per pound
- Muscle building: 0.8–1.0g per pound
- Aggressive cut / high cardio: up to 1.2g per pound
For our 175 lb example person: minimum 123g, optimal for fat loss 140–175g per day.
How Long Until You See Results?
At 250 cal deficit: ~0.5 lb/week fat loss. At 500 cal deficit: ~1 lb/week. Expect to see measurable changes on the scale in 2–3 weeks and visible body composition changes in 6–8 weeks.
Track for 2 weeks. If the scale doesn't move as expected, adjust calories by ±100–200 per day. Metabolic calculators have 10–15% margin of error — the real feedback loop is your actual results.