IIFYM Macro Calculator
Use lean body mass to set protein and fat targets, then allocate remaining calories to carbohydrates. Adjust multipliers to align with your physique, performance, or dieting goals.
Estimate using calipers, smart scale, or DEXA scan if possible.
Macro Breakdown
Protein
121 g
486 kcal (22.1%)
Fat
63 g
567 kcal (25.8%)
Carbohydrates
287 g
1147 kcal (52.1%)
Per meal (≈4 meals)
Protein 30.4 g • Fat 15.7 g • Carbs 71.7 g
How to Use This Calculator
Calculate or estimate body fat
Lean body mass influences protein requirements. Use calipers or smart scale estimates; update regularly as composition changes.
Set realistic multipliers
Protein at 0.8–1.1 g/lb lean mass supports muscle retention. Fats at 0.3–0.45 g/lb total weight maintain hormones. Adjust based on dietary preference.
Adjust and track
Implement the macro targets for several weeks, track weight and performance, then tweak calories or macro ratios as needed.
Formula
Lean mass (kg) = Weight × (1 − Body fat %)
Protein grams = Lean mass × Protein multiplier
Fat grams = Weight × Fat multiplier
Carb grams = (Calories − Protein kcal − Fat kcal) ÷ 4
- Protein calories = grams × 4, fat calories = grams × 9, carbohydrate calories = grams × 4.
- Ensure protein and fat calories do not exceed total calorie targets.
- For ketogenic plans, lower carbs manually and adjust fats upward.
Full Description
The If It Fits Your Macros (IIFYM) approach centres on meeting daily macro targets rather than rigid food lists. By basing protein and fat on body composition, you preserve lean mass while supporting hormonal health. Remaining calories go to carbohydrates, offering flexibility for training demands and personal preference.
Combine macro planning with micronutrient-dense foods, adequate fibre, hydration, and sleep. Adjust targets as your weight, body fat, or performance goals change.
Frequently Asked Questions
Do I have to track every gram?
Precision helps initially. Over time you can estimate portions or adopt flexible ranges (±5–10 g) while monitoring progress.
What if I eat more protein than planned?
Slightly higher protein is fine; adjust carbs or fats downward to stay within calories if body composition goals require it.
How often should I recalculate macros?
Update every 4–6 weeks or after significant weight/body fat changes. Athletic seasons may require more frequent adjustments.
Can IIFYM work for weight loss?
Yes. Maintain a calorie deficit while meeting macro targets to preserve lean mass and manage hunger.