Macro Calculator
Calculate your optimal daily macronutrient split (protein, carbs, and fat) for fat loss, muscle building, or athletic performance.
Range: 15 – 80
Range: 0 – 9
Range: 0 – 11
What Are Macros?
Macronutrients (or "macros") are the nutrients your body requires in large amounts to supply energy, support cell division, and maintain metabolic function. There are three primary macros:
1. Protein: Critical for building and repairing muscle tissues, organ structures, skin, and enzymes.
2. Carbohydrates: The body's preferred source of energy, converted into glycogen to fuel muscles and brain activity.
3. Fats: Essential for hormone synthesis, vitamin absorption (A, D, E, K), brain function, and joint cushioning.
While calorie counting determines whether you lose or gain weight, tracking your macro split determines what kind of weight you lose or gain (e.g., losing fat instead of muscle).
Energy Density of Macronutrients
To calculate your macro targets, you must understand the calorie values of each gram:
- Protein: 4 calories per gram
- Carbohydrates: 4 calories per gram
- Fats: 9 calories per gram
Because fat contains more than double the energy density of protein and carbs, even small portions of high-fat foods can rapidly increase your calorie intake.
Popular Macro Splits
Depending on your fitness goals, different macronutrient ratios can optimize your progress:
| Goal & Ratios | Protein % | Carbs % | Fats % | Ideal For |
|---|---|---|---|---|
| **Balanced (30/40/30)** | 30% | 40% | 30% | General health, athletic maintenance, moderate endurance |
| **High Protein (40/40/20)** | 40% | 40% | 20% | Fat loss (preserving muscle in a deficit), bodybuilding cuts |
| **Keto (30/5/65)** | 30% | 5% | 65% | Therapeutic ketosis, rapid insulin management, fat-adaptation |
How to Calculate Your Macros (Mifflin-St Jeor)
Step 1: Find BMR
Using the Mifflin-St Jeor formula, calculate your rest energy:
- Men: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5
- Women: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161
Step 2: Multiply by Activity Level
Multiply BMR by your physical activity factor (1.2 to 1.9) to find maintenance calories (TDEE).
Step 3: Adjust for Goal
- Lose Weight: Subtract 500 calories (typical 0.5 kg loss/week).
- Gain Muscle: Add 250–500 calories (slow lean bulk).
Step 4: Split Into Grams
Multiply total calories by the macro percentage and divide by its energy density:
- Protein Grams = (Total Calories × Protein%) / 4
- Carb Grams = (Total Calories × Carbs%) / 4
- Fat Grams = (Total Calories × Fat%) / 9
Related Resources
Related Calculators
- Calorie Calculator — Match macros to your daily calorie target.
- Protein Calculator — Focus on daily protein requirements.
External Authority Resources
- National Academies Acceptable Macronutrient Ranges — Official AMDR values guidelines.
- Harvard Nutrition Source on Macronutrients — Evidence-based advice on diet splits.
Sources & Citations
- Mifflin MD, St Jeor ST, et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241-7.
- Phillips SM, Van Loon LJ. Dietary protein for athletes: from requirements to optimum adaptation. J Sports Sci. 2011;29 Suppl 1:S29-38.
- Jeukendrup AE. Carbohydrate intake during exercise and performance. Nutrition. 2004;20(7-8):669-677.
Protein Distribution for Maximum Muscle Protein Synthesis
Total daily protein matters — but so does how you distribute it. Research on muscle protein synthesis (MPS) shows that it responds to individual protein doses, not just daily totals. Aim for 4–5 protein servings per day, each providing 30–40 g of protein, to maximise MPS throughout the day.
High-quality protein sources that provide all essential amino acids (particularly leucine, which triggers MPS):
| Source | Protein per 100g |
|---|---|
| Chicken breast | 31g |
| Tuna (canned, in brine) | 26g |
| Greek yoghurt | 10g |
| Eggs (2 large) | 12g |
| Whey protein powder | 78–85g |
| Lentils (cooked) | 9g |
Use our Protein Calculator to find your personalised daily protein target by body weight and activity level.
Carbohydrate Timing and Training Performance
Carbohydrates are stored as glycogen in muscles and the liver, serving as the primary fuel for high-intensity training. Strategic carbohydrate timing maximises glycogen availability when you need it most:
Pre-workout (1–2 hours before training):
Eat 30–60 g of complex carbohydrates (oats, rice, potato) to top up glycogen stores. This directly improves training performance, especially for sessions lasting longer than 60 minutes.
Post-workout (within 2 hours):
30–60 g of fast-digesting carbohydrates alongside protein maximises insulin-stimulated muscle protein synthesis and glycogen replenishment. This is the most important nutrient timing window for muscle gain.
Rest days:
Slightly reduce carbohydrates on rest days (by 40–70 g) as glycogen demand is lower. Maintain protein constant every day.
The Quality of Dietary Fat
Not all fats are equal. The macro calculator provides a fat gram target, but the type of fat matters:
Prioritise:
- Omega-3 fatty acids (oily fish, walnuts, chia seeds) — anti-inflammatory, support insulin sensitivity and muscle recovery
- Monounsaturated fats (olive oil, avocado, almonds) — cardiovascular benefits, hormone support
Moderate:
- Saturated fats (red meat, dairy) — not inherently harmful in moderation; support testosterone in resistance athletes
Minimise:
- Trans fats (industrial hydrogenated oils) — strongly linked to cardiovascular disease; avoid where possible
How to Adjust Macros Over Time
Your macro targets are not permanent. Adjust every 4–6 weeks based on:
1. Scale weight trend: If losing >0.7 kg/week, increase calories by 100–150 kcal; if losing <0.2 kg/week and goal is fat loss, reduce by 100–150 kcal
2. Training performance: If strength is declining consistently, increase carbohydrates
3. Body composition photos: Visual changes are the most reliable indicator of body recomposition progress
4. Hunger and adherence: A macro split you can't sustain is worthless — adjust proportions to maximise adherence
Frequently Asked Questions
What is the best macro split for fat loss?
A high-protein split (30–35% protein, 35–40% carbs, 25–30% fat) is most effective for fat loss with muscle preservation. Protein should be at minimum 1.6 g/kg/day. The exact carb/fat split is less critical — both approaches work at equal calories and protein.
Should I count macros or calories?
Counting macros automatically controls calories (since every gram of each macro has a fixed calorie value) while also optimising body composition. For most people, hitting protein targets while eating at appropriate calories is the most efficient approach — tracking every carb and fat gram is optional.
What is a good macro split for building muscle?
For muscle gain (slight caloric surplus): approximately 25–30% protein, 45–50% carbohydrates, 20–25% fat. Carbohydrates fuel training, protein drives muscle synthesis, and fat supports hormones. Protein should be 1.6–2.2 g/kg/day.
Can I change my macro ratios without changing calories?
Yes — you can shift the proportion of each macro while keeping total calories constant. If you reduce fat by 20 g (180 kcal), you can add 45 g of carbohydrates (180 kcal) without changing your total daily intake.
Are keto macros effective for muscle building?
Keto (very low carbohydrate) is less optimal for muscle building than higher-carbohydrate approaches because carbohydrates are the preferred fuel for anaerobic exercise (weight training). Keto may suit endurance athletes or those with specific therapeutic goals, but for strength training and hypertrophy, higher carbohydrate intake generally supports better performance.
Frequently Asked Questions
Macronutrients are the primary nutrients your body needs in large quantities to function: Protein (for muscle repair and enzyme function), Carbohydrates (for energy), and Fat (for hormone production and cellular health).
Protein contains 4 calories per gram, Carbohydrates contain 4 calories per gram, and Fat contains 9 calories per gram. This is why high-fat foods are much more calorie-dense.
A high-protein macro split (like 40% Carb, 40% Protein, 20% Fat) is highly effective for fat loss. High protein intake helps preserve lean muscle mass during a calorie deficit and increases fullness (satiety).
The Ketogenic diet is a very low-carb, high-fat diet. A typical Keto split is 5% Carbohydrates, 30% Protein, and 65% Fat. By restricting carbs, the body enters a metabolic state called ketosis, burning fat for energy.
Track the weight of the foods you eat using a kitchen scale, and log them in a database tool. Pay attention to the raw gram targets (e.g. 150g protein) rather than just calories to hit your macro goals.