Macro Calculator

About the Macro Calculator

A macro calculator (macronutrient calculator) determines the ideal daily amounts of protein, carbohydrates, and fat your body needs based on your calorie target, body composition goal, and dietary preferences. "Macros" is short for macronutrients — the three main classes of nutrients that provide calories: protein (4 calories per gram), carbohydrates (4 calories per gram), and fat (9 calories per gram). Knowing your macros moves you beyond simply counting total calories to understanding the quality and composition of those calories. Two people eating the same 2,000 calories per day will have dramatically different body composition outcomes depending on whether those calories come from predominantly protein and vegetables versus predominantly refined carbs and processed fat. Our free macro calculator uses your TDEE, goal (fat loss, maintenance, or muscle building), and body weight to determine science-based macronutrient targets — including protein requirements per pound of body weight, fat minimums for hormonal health, and carbohydrate fill to complete the calorie budget. It works for standard macros, IIFYM (If It Fits Your Macros), ketogenic diet (very low carb, high fat), low-carb, and high-protein approaches.

How It Works

Step 1: Calculate your TDEE and set a calorie target (deficit for fat loss, surplus for muscle gain, maintenance for recomposition). Step 2: Set protein. The evidence-based range for body composition goals is 0.7-1.0g per pound of body weight (1.6-2.2g per kg). Higher end (1.0g/lb) is recommended during a calorie deficit to maximise muscle preservation. Example: 170 lb person targeting fat loss at 0.85g/lb = 145g protein x 4 cal/g = 580 calories from protein. Step 3: Set fat minimum. Dietary fat is essential for hormone production, fat-soluble vitamin absorption, and cell membrane integrity. Minimum recommended: 0.35-0.45g per pound of body weight. 170 lb x 0.40g = 68g fat x 9 cal/g = 612 calories from fat. Step 4: Fill remaining calories with carbohydrates. If TDEE - 500 = 1,900 calorie target: 1,900 - 580 (protein) - 612 (fat) = 708 carbohydrate calories / 4 = 177g carbs. Final macros: 145P / 177C / 68F = 1,900 total calories.

Tips & Best Practices

• ✓Protein is the most important macro for body composition: it preserves muscle during a calorie deficit, creates satiety that reduces hunger, has the highest thermic effect (burns more calories during digestion), and supports recovery from training.
• ✓The ketogenic diet macro split is typically 70-75% fat, 20-25% protein, and 5% or less carbohydrates (usually under 25-50g/day). The very low carb intake forces the liver to produce ketones from fat as the primary fuel source.
• ✓Fat is not the enemy: dietary fat is essential for testosterone production, estrogen balance, cortisol regulation, and the absorption of vitamins A, D, E, and K. Dropping fat below 0.3g/lb of body weight risks hormonal disruption.
• ✓Carbohydrates are the body's preferred energy source for high-intensity exercise. Athletes and those training 4+ days per week generally perform better with higher carbohydrate intake — 45-65% of total calories — compared to sedentary individuals.
• ✓Fibre, a form of carbohydrate, does not significantly raise blood sugar and is not typically tracked as a macro in most diet approaches. General recommendation: 25-38g of dietary fibre per day for digestive health, satiety, and blood sugar management.
• ✓Alcohol (7 calories per gram) has no nutritional value and is often tracked separately from macros. In practice, alcohol calories often displace protein and carbohydrates, complicating macro tracking.
• ✓Reverse dieting: when transitioning out of a calorie deficit, gradually increasing carbohydrates (25-50g per week) while maintaining protein allows for controlled weight restoration with minimal fat regain.
• ✓Tracking macros in apps: popular macro tracking apps like MyFitnessPal, Cronometer, and MacroFactor scan barcodes and have databases of millions of foods, making macro tracking practical for everyday eating.

Who Uses This Calculator

Bodybuilders and physique competitors use macro calculators to dial in precise nutritional targets for every phase of their competitive calendar — high-protein, moderate-carb cuts during contest prep and higher-carb maintenance and bulk phases in the off-season. People following IIFYM (If It Fits Your Macros) use the calculator to set daily targets and then eat any foods they choose as long as the macros are hit at the end of the day. Individuals transitioning from calorie counting to macro tracking use it to understand the composition of their calories for the first time. Registered dietitians and sports nutritionists use macro calculators as the starting point for personalised meal plans for athletes and body composition clients. Keto dieters use the calculator to set their specific carbohydrate limit and fat target required to maintain ketosis. Personal trainers provide macro targets to clients as part of comprehensive coaching programmes. People managing type 2 diabetes or insulin resistance use macro information to understand the carbohydrate content of their diet and its blood sugar implications.