Macronutrient Ratio Formula
Set protein by body weight, fat by minimum essential threshold, fill the rest with carbs. Calorie targets first, ratios second — the ratio that worked at 2,500 calories doesn't work at 1,800.
Formula
Copy the exact expression or work through it step by step below.
protein_g = mass_kg × protein_target_g_per_kg
fat_g = mass_kg × fat_target_g_per_kg
carb_g = (total_cal − protein_g·4 − fat_g·9) / 4 Variables
protein_g
Daily protein
Grams. 1.6 g/kg minimum for muscle retention, 2.2 g/kg upper bound for active lifters in a deficit. 4 cal/g.
fat_g
Daily fat
Grams. 0.6 g/kg minimum to support sex-hormone production; 1.0 g/kg is a more common comfortable upper bound. 9 cal/g.
carb_g
Daily carbohydrate
Grams. The remainder after protein and fat are set. 4 cal/g.
total_cal
Daily calorie target
From TDEE × goal multiplier (deficit, maintenance, surplus).
Step By Step
- 1
Pin protein first. 1.8–2.0 g/kg is the working range for almost everyone training with intent.
78 kg × 1.8 = 140.4 g protein → 561.6 cal.
- 2
Set fat to its minimum healthy share — 0.8 g/kg is a sane default.
78 × 0.8 = 62.4 g fat → 561.6 cal.
- 3
Subtract protein and fat calories from the total target. The remainder belongs to carbohydrate.
2,303 cal − 561.6 − 561.6 = 1,179.8 cal → 1,179.8 / 4 = 294.95 g carbs.
- 4
Translate to a percentage if you want a ratio label. Note that the ratio will shift as calories move.
Protein 24% / Fat 24% / Carb 51%.
Worked Example
78 kg adult, 2,303 cal target, 1.8 g/kg protein, 0.8 g/kg fat
Body mass (kg)
78
Daily calories
2,303
Protein target
1.8 g/kg
Fat target
0.8 g/kg
P 140.4 g (562 cal) | F 62.4 g (562 cal) | C 295 g (1,180 cal). Total 2,304 cal.
Macros: 140 P / 62 F / 295 C. Ratio 24/24/51. Protein and fat hit absolute targets first; carbs absorb calorie-target changes.
Common Variations
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Sources & References
- Helms ER et al. A systematic review of dietary protein during caloric restriction in resistance trained lean athletes — International Journal of Sport Nutrition and Exercise Metabolism
- Morton RW et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength — British Journal of Sports Medicine