Macro Calculator (IIFYM): Daily Protein, Fat & Carb Targets
Get your personalised macronutrient breakdown — protein, fat, and carbs — tailored to your weight, goal, and activity level. Includes calorie targets and a visual macro split.
What Is IIFYM? (If It Fits Your Macros)
IIFYM — If It Fits Your Macros— is a flexible dieting approach that prioritises hitting your daily protein, fat, and carbohydrate targets over restricting specific foods. Rather than labelling foods as “clean” or “off limits,” IIFYM lets you eat any food as long as it fits within your macro budget for the day.
This calculator is the starting point for an IIFYM approach: it calculates your personalised macro targets based on your goals. From there, you track your daily intake (using an app like MyFitnessPal or Cronometer) and allocate your macros however you choose — whole foods, restaurant meals, or the occasional treat.
IIFYM vs Clean Eating: Key Difference
Clean eating restricts specific foods. IIFYM restricts nothing — it only sets nutrient targets. Research consistently shows that matched-calorie and matched-protein diets produce identical body composition outcomes regardless of food source. IIFYM typically produces better long-term adherence because psychological restriction is eliminated.
How Macros Affect Your Body Composition
All three macronutrients serve distinct roles. Protein provides the amino acids that build and repair muscle tissue. Fat supports hormone production, brain function, and fat-soluble vitamin absorption. Carbohydrates are the body's preferred fuel for high-intensity exercise and replenish muscle glycogen after training.
While total calories determine whether you gain or lose weight, macro ratios determine whether that weight change is primarily fat or muscle. Higher-protein diets during a calorie deficit preserve significantly more lean mass than lower-protein diets at the same calorie level.
| Macro | Calories/g | Primary Role | Typical Range |
|---|---|---|---|
| Protein | 4 kcal/g | Muscle building, satiety, thermic effect | 25–35% of calories |
| Fat | 9 kcal/g | Hormones, brain, fat-soluble vitamins | 20–35% of calories |
| Carbohydrates | 4 kcal/g | Exercise fuel, glycogen, brain function | 30–50% of calories |
Frequently Asked Questions
What are macros?
Macros (macronutrients) are the three main categories of nutrients that provide calories: protein (4 kcal/g), carbohydrates (4 kcal/g), and fat (9 kcal/g). Tracking macros gives you much more control over body composition than tracking calories alone, because the ratio of protein to carbs and fat significantly affects muscle retention, satiety, and energy levels.
How much protein, fat, and carbs should I eat per day?
It depends on your goal. For muscle gain: ~1.6–2.2 g/kg protein, 25–35% of calories from fat, remainder from carbs. For weight loss: ~1.2–2.0 g/kg protein (higher to preserve muscle), moderate fat, lower carbs. For maintenance: ~0.8–1.2 g/kg protein, balanced fat and carbs. This calculator sets these ratios based on your selected goal.
Should I track macros or just calories?
Tracking macros gives you more information than calories alone. Two people eating 2,000 kcal can have very different body composition outcomes if one eats 200g of protein and the other eats 50g. For fat loss with muscle preservation, hitting your protein target matters most. For general health and weight stability, calories are the primary lever.
Do I need to hit my macros exactly every day?
Consistency over weeks matters far more than perfection on any single day. Aim to hit your protein target most days (it has the biggest impact on body composition). Fat and carb targets have more flexibility — being within 10–15% on average is sufficient. A flexible approach reduces stress and improves long-term adherence.
What is the best macro ratio for weight loss?
Higher-protein ratios work best for weight loss: 30–40% of calories from protein, 25–35% from fat, 25–40% from carbs. The most important factor is a calorie deficit. Within that deficit, higher protein (1.2–2.0 g/kg) is the single best macro adjustment — it preserves muscle, increases satiety, and has the highest thermic effect.
What is the best macro ratio for muscle gain?
For muscle gain: protein at 25–35% of calories (1.6–2.2 g/kg body weight), fat at 25–30%, carbohydrates at 40–50% (or remainder). Carbohydrates fuel high-intensity training and replenish muscle glycogen, so they are valuable for athletes and those lifting hard. A 10% calorie surplus above TDEE supports muscle protein synthesis.