Macronutrient targets are determined by your total daily calories, your goal, and your body weight. Protein is prioritised first (it is calculated per kg of body weight), then fat (as a % of calories), and carbohydrates fill the remainder.
Goal
Protein
Fat
Carbs
Weight Loss
2.0–2.4 g/kg (high, to preserve muscle)
25%
Remainder
Maintenance
1.6–2.0 g/kg
30%
Remainder
Muscle Gain
1.8–2.2 g/kg
25%
Remainder
Athletic Performance
1.6–2.0 g/kg
20%
High — remainder
Each gram of protein = 4 kcal | each gram of carbs = 4 kcal | each gram of fat = 9 kcal
Frequently Asked Questions
Macronutrients (macros) are the three main energy-providing nutrients: protein, carbohydrates, and fat. Every food you eat contains a combination of these. Tracking macros — not just calories — helps you achieve body composition goals like fat loss while preserving muscle, or muscle gain without excessive fat.
For muscle retention or growth, research supports 1.6–2.2 g of protein per kg of body weight per day. The RDA (0.8 g/kg) is just enough to prevent deficiency — it is not optimal for active people. Aim for the higher end if you are in a calorie deficit or training intensely.
Dietary fat is essential for hormone production, vitamin absorption (A, D, E, K), and brain function. Very low fat diets (under 15% of calories) can impair testosterone and oestrogen levels. Most nutrition guidelines recommend fat at 20–35% of total daily calories from predominantly unsaturated sources.
The classic ketogenic diet is characterised by very high fat, very low carbohydrate intake: typically fat 70–75%, protein 20–25%, and carbohydrates 5–10% of total calories (usually under 20–50g of net carbs per day). This forces the body into ketosis — a metabolic state where fat is burned for fuel instead of glucose. The keto diet is used clinically for epilepsy and is popular for weight loss, but it is restrictive and may not suit everyone. Consult a healthcare professional before starting a ketogenic diet, especially if you have existing health conditions.
For bulking (muscle gain in a calorie surplus), a common macro split is: protein 25–30%, carbohydrates 45–55%, fat 20–25%. Higher carbohydrate intake supports training intensity and glycogen replenishment. For cutting (fat loss in a calorie deficit), protein increases to preserve muscle: protein 30–40%, carbohydrates 30–40%, fat 20–30%. In both phases, maintaining a high protein intake (1.6–2.2 g/kg body weight) is the most important factor for body composition. Ratios should be adjusted based on individual response and training type.
The official RDA for protein is 0.8 g per kg of body weight — but this is the minimum to prevent deficiency, not the optimal amount for an active person. For muscle preservation and growth, research consistently supports 1.6–2.2 g/kg/day. Older adults benefit from the higher end (2.0–2.5 g/kg) to counteract age-related muscle loss (sarcopenia). Athletes in heavy training or a calorie deficit may benefit from up to 2.4 g/kg. Spreading protein intake across 3–5 meals (targeting 20–40 g per meal) maximises muscle protein synthesis. Consult a sports dietitian for personalised guidance.
Tracking total calories is sufficient for basic weight management — if you eat fewer calories than you burn, you will lose weight regardless of macros. However, tracking macros gives you additional control over body composition: ensuring enough protein preserves muscle during a deficit, carb timing can improve training performance, and fat intake supports hormone health. For general health and modest weight management, calorie tracking alone is simpler and effective. For body composition goals (building muscle while losing fat), macro tracking provides a meaningful advantage. Either approach is far more effective when combined with consistent habits and whole-food eating.
IIFYM (If It Fits Your Macros) is a flexible dieting approach where you can eat any food as long as it fits within your daily macronutrient targets. The principle is that body composition is determined by macros and calories — not by whether your food is "clean" or "dirty." This approach reduces the psychological burden of strict food rules and improves adherence for many people. However, food quality still matters for micronutrients, fibre, and satiety — a diet of pizza and sweets that hits macro targets will lack vitamins, minerals, and fibre. Most nutrition professionals recommend applying IIFYM with a foundation of minimally processed whole foods.
Carb cycling is a nutritional strategy where carbohydrate intake is alternated between high, moderate, and low levels on different days — typically aligned with training intensity. On heavy training days, more carbs fuel performance and recovery; on rest or light days, carbs are reduced to encourage fat burning while keeping overall weekly calories in check. It is used by athletes, bodybuilders, and physique competitors. Evidence for carb cycling's superiority over consistent macro intake in the general population is limited, and the additional complexity makes it unsuitable for most beginners. It is best suited to experienced trainees with specific performance or body composition goals. Consult a sports dietitian before implementing a carb cycling protocol.
IIFYM (If It Fits Your Macros), also called flexible dieting, is an approach to nutrition where you track your daily targets for protein, carbohydrates, and fat rather than following a rigid list of "allowed" or "forbidden" foods. As long as a food fits within your remaining macro budget for the day, you can eat it — whether that's chicken and broccoli or a slice of pizza. IIFYM rejects the notion of clean eating as a prerequisite for body composition progress, focusing instead on hitting daily macronutrient targets within an appropriate calorie total. Research supports that body composition outcomes are primarily driven by energy balance and macronutrient intake rather than specific food choices. The flexibility of IIFYM improves long-term dietary adherence. However, it should not be used to justify consistently low-micronutrient diets — fibre, vitamins, and minerals still matter for overall health. Consult a healthcare professional or registered dietitian for personalised guidance.
About This Macro Calculator
This free macro calculator computes your recommended daily intake of protein, carbohydrates, and fat in grams and as a percentage of total calories, based on your TDEE and selected goal (weight loss, maintenance, or muscle gain).
Macronutrients determine body composition more precisely than calorie counting alone. Adequate protein preserves muscle during a calorie deficit; the carbohydrate and fat split is adjusted based on your preferred dietary approach and activity type.
When to use this calculator
Setting daily macro targets for a structured nutrition plan
Adjusting protein intake during a cutting or bulking phase
Calculating macros for a specific calorie target
Comparing high-carb vs high-fat macro distributions
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Learn what macronutrients are, how macro ratios differ by goal (fat loss, muscle gain, endurance), how to calculate your daily protein, carbs, and fat targets, and why macros matter beyond calories.
