Macro Calculator — Protein, Carb & Fat Intake (Free)
Unit System
Gender
About This Tool
The Macro Calculator calculates your daily calorie needs and ideal macronutrient targets (protein, carbs, and fat) for muscle gain, fat loss, or weight maintenance. It supports metric and imperial units and customizable macro splits.
How to Use
- Choose your preferred unit system and gender.
- Enter your age, weight, and height.
- Select your typical weekly activity level.
- Select your primary goal (e.g. Weight Loss, Maintain, or Gain Muscle).
- Choose a macronutrient ratio preset to view your custom grams and calories target.
Detailed Explanation & Worked Example
Macronutrients (or "macros") are the nutrient categories our body needs in large amounts to function properly: proteins, carbohydrates, and fats. Each macro provides a specific amount of energy per gram:
- Proteins: 4 calories per gram. Essential for muscle building, cellular repair, and immune function.
- Carbohydrates: 4 calories per gram. The body's primary source of quick energy.
- Fats: 9 calories per gram. Vital for hormone regulation, brain function, and nutrient absorption.
The Mifflin-St Jeor Formula
The calculator calculates your BMR (Basal Metabolic Rate) using the Mifflin-St Jeor formula, widely considered to be the most accurate for healthy adults:
- Men:
BMR = 10 * weight (kg) + 6.25 * height (cm) - 5 * age (years) + 5 - Women:
BMR = 10 * weight (kg) + 6.25 * height (cm) - 5 * age (years) - 161
Once BMR is calculated, we multiply it by an activity factor to find your TDEE (Total Daily Energy Expenditure). Calories are then subtracted for weight loss goals or added for muscle gain targets.
Macro Ratio Recommendations
Depending on your lifestyle and training, different macro ratios may be suitable:
- Balanced: A versatile ratio suitable for general health, energy, and moderate exercise.
- High Protein: Excellent for muscle retention during weight cuts or for active weightlifters.
- Low Carb: Helpful for individuals seeking to manage insulin levels or support endurance goals.
- Keto: Emphasizes high fats and extremely low carbohydrates, forcing the body to burn fat for energy (ketosis).