Macro Calculator — Protein, Carbs & Fat

Macronutrient ratios divide your daily calories among protein, carbohydrates and fat. Common starting points are 30/40/30 (balanced), 40/30/30 (high protein for muscle gain) or 25/45/30 (endurance). Each gram of protein and carbohydrate provides 4 kcal, while fat provides 9 kcal, and alcohol, treated by some as a fourth macronutrient, provides 7 kcal. The three do different jobs: protein builds and repairs muscle and tissue, carbohydrate is the main energy source, and fat supports hormone production, vitamin absorption and energy storage.

This calculator first estimates your Total Daily Energy Expenditure, then splits those calories into grams of each macronutrient based on your chosen goal. For weight loss, protein is kept high, at around 30 to 40%, to preserve muscle mass, while carbohydrates and fat are reduced. For muscle gain, both protein and carbohydrates are set higher.

There is a second route to the same place, and it is the one most coaches use. Start from your expenditure, typically 2,000 to 3,000 kcal a day depending on size and activity. Set protein by bodyweight at 1.6 to 2.2 g per kg, then fat at 0.6 to 1.0 g per kg with a floor of 30 g a day, and let carbohydrate take whatever calories remain. For a 70 kg adult eating 2,200 kcal, that gives 140 g of protein at 560 kcal, 60 g of fat at 540 kcal, and the last 1,100 kcal as 275 g of carbohydrate.

Goals pull the ratio in different directions. Losing weight works best at roughly 40% protein, 30% carbohydrate and 30% fat, since protein is what protects muscle in a deficit. Gaining muscle flips it to about 25% protein, 45% carbohydrate and 30% fat, because carbohydrate fuels the training that drives the gain. Endurance athletes push carbohydrate further still, to around 55%, with 20% protein and 25% fat, to keep glycogen stores full. A ketogenic diet sits at the far end of the range with 5 to 10% carbohydrate and 65 to 90% fat.

Macro tracking is widely used alongside calorie counting to improve body composition. The NHS recommends that fat should not exceed 35% of total energy and that saturated fat should stay below 11%, and its Eatwell Guide sets out a general-health pattern of roughly 50% carbohydrate, 35% fat and 15% protein. Fitness and weight-loss circles usually run protein higher, at 25 to 35%, and carbohydrate lower. A Mediterranean pattern, with moderate protein, carbohydrate largely from vegetables and pulses, and fat from olive oil and nuts, fits comfortably inside those limits.

Hitting the numbers comes down to knowing a handful of foods. Chicken breast carries 31 g of protein per 100 g, turkey 29 g, tinned tuna 28 g, salmon 25 g, eggs 13 g per 100 g or 6 g each, Greek yoghurt 10 g, cottage cheese 12 g, lentils and chickpeas 9 g and tofu 8 g. On the carbohydrate side, oats give 60 g per 100 g, cooked brown rice 70 g, sweet potato 20 g, potato 17 g, a slice of wholemeal bread 10 to 15 g, a banana 23 g and an apple 14 g. Fat comes mainly from olive oil, avocado at 15 g per 100 g, almonds at 50 g and walnuts at 65 g.

Adjust ratios to suit your preferences and monitor progress over several weeks rather than several days. MyFitnessPal has the largest UK food database, Cronometer the better nutrient detail, with Lifesum and Carb Manager as alternatives. A kitchen scale at £5 to £15 earns its keep, because eyeballing portions is typically 30 to 50% out. Weigh dry foods raw, since 50 g of oats turns into 200 g once it has absorbed water. Logging meals in advance makes the plan easier to stick to, and landing within 10% is close enough. Protein is the number worth chasing precisely, while carbohydrate and fat can move around training and social plans.