Macro Calculator

Macronutrients — protein, carbohydrate and fat — are the three categories of nutrient that provide the body with energy (unlike micronutrients such as vitamins and minerals, which support metabolic processes but contribute negligible calories). Protein and carbohydrate each provide 4 kilocalories per gram, while fat provides 9 kilocalories per gram — more than double, because fat is a more energy-dense molecule. A "macro split" describes what percentage of your total daily calories comes from each of the three, and different splits suit different goals, preferences and metabolic responses, which is why this calculator offers four common presets rather than a single fixed ratio. This tool builds on the same calculation chain as the BMR and Calorie calculators: it estimates your BMR with the Mifflin-St Jeor equation, multiplies by your activity level to get TDEE, and applies your chosen goal adjustment (−500 kcal/day for weight loss, 0 for maintenance, +500 kcal/day for weight gain — the same tiers used by the Calorie Calculator) to arrive at a daily calorie target. That target is then split into grams using your chosen macro percentages: grams of protein or carbohydrate = (calorie target × percentage) ÷ 4, and grams of fat = (calorie target × percentage) ÷ 9. The four presets reflect genuinely different, evidence-informed approaches rather than arbitrary numbers. Balanced (40% carbohydrate / 30% protein / 30% fat) approximates general population dietary guidelines and suits most people without a specific performance or medical goal. Low-Carb (25% carbohydrate / 35% protein / 40% fat) reduces carbohydrate below the general-population average — often chosen for appetite control or blood sugar management — while keeping protein high enough to help preserve muscle. High-Protein (30% carbohydrate / 40% protein / 30% fat) prioritises protein above the other two, a split commonly used during a calorie deficit (to protect lean muscle mass while losing fat) or during a muscle-building phase, since protein is the macronutrient most directly tied to muscle protein synthesis and also has the highest satiety value per calorie of the three. Keto (5% carbohydrate / 25% protein / 70% fat) restricts carbohydrate sharply enough to shift the body toward producing ketones from fat as its primary fuel source (a metabolic state called ketosis) — this preset is intentionally aggressive and is not suitable for everyone; anyone with diabetes, kidney conditions, or who is pregnant should not attempt a ketogenic split without direct medical supervision. Protein deserves particular attention regardless of which preset you choose, because it plays a role none of the other macros fully replace: it is the primary building block for muscle tissue repair and growth, it has the highest thermic effect of food (your body burns more calories digesting protein than digesting carbohydrate or fat), and it is the most satiating macronutrient gram-for-gram, which is a major practical factor in sticking to a calorie target without excessive hunger. This is why the High-Protein preset is popular specifically during weight loss, where preserving muscle while losing fat is the goal, rather than simply losing weight in whichever tissue happens to go first. It is worth being clear about what macro targets do not capture: they say nothing about food quality, fibre intake, micronutrient adequacy, or the difference between, say, 100g of carbohydrate from vegetables versus 100g from refined sugar — both count identically toward a carbohydrate gram target, but they are not nutritionally equivalent. Macro tracking is a useful tool for people with a specific body-composition or performance goal who already have a reasonably healthy diet pattern in place; it is not, by itself, a complete definition of a healthy diet, and it should be layered on top of, not instead of, general good nutrition (adequate fibre, a variety of whole foods, and adequate micronutrient intake).