Calculate your daily protein, carbohydrate, and fat targets based on your body weight and fitness goals.
Sedentary (little to no exercise)
Lightly Active (light exercise/sports 1-3 days/week)
Moderately Active (moderate exercise/sports 3-5 days/week)
Very Active (hard exercise/sports 6-7 days/week)
Extra Active (very hard exercise/sports & physical job)
Maintain Weight
Muscle Gain
Fat Loss
Your Daily Macronutrient Targets:
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Protein (g)
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Carbohydrates (g)
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Fat (g)
Understanding Macronutrient Calculation
Macronutrients, or "macros," are the nutrients your body needs in large amounts to function: protein, carbohydrates, and fats. They provide energy (calories) and are essential for building and repairing tissues, regulating bodily processes, and maintaining overall health.
Calculating your target macronutrient intake is a fundamental step in achieving specific fitness and body composition goals, whether it's building muscle, losing fat, or simply maintaining your current physique.
How Your Macros Are Calculated
This calculator uses a common approach to estimate your daily macronutrient needs. The process typically involves these steps:
Basal Metabolic Rate (BMR) Estimation: While this calculator simplifies it, BMR is the number of calories your body burns at rest. It's influenced by factors like age, sex, weight, and height.
Total Daily Energy Expenditure (TDEE) Calculation: This takes your BMR and multiplies it by an activity factor to estimate the total calories you burn in a day, considering your exercise and daily movement. The activity levels are categorized as follows:
Sedentary: BMR x 1.2
Lightly Active: BMR x 1.375
Moderately Active: BMR x 1.55
Very Active: BMR x 1.725
Extra Active: BMR x 1.9
For simplicity, this calculator directly estimates calories based on weight and activity level, approximating TDEE.
Calorie Adjustment for Goals:
Maintenance: Calories are set around TDEE.
Muscle Gain: A surplus of 250-500 calories is added to TDEE.
Fat Loss: A deficit of 250-500 calories is created from TDEE.
Macronutrient Distribution: Once a target daily calorie intake is determined, it's broken down into protein, carbohydrates, and fats based on recommended ratios, which vary by goal.
Protein: Crucial for muscle repair and growth. A common target is 1.6 to 2.2 grams per kilogram of body weight, or a percentage of total calories.
Fat: Essential for hormone production and nutrient absorption. Typically set at 20-30% of total calories.
Carbohydrates: Provide the primary source of energy. The remaining calories after protein and fat are allocated to carbohydrates.
Example Calculation
Let's consider a person who weighs 75 kg, is moderately active, and wants to build muscle.
Body Weight: 75 kg
Activity Level: Moderately Active
Goal: Muscle Gain
The calculator might estimate a TDEE of around 2600 calories. For muscle gain, it adds a surplus, bringing the target to approximately 2900 calories.
Using common ratios:
Protein: Let's aim for 2.0g per kg of body weight. 75 kg * 2.0 g/kg = 150 g of protein. (150g * 4 calories/g = 600 calories)
Fat: Let's target 25% of total calories. 2900 calories * 0.25 = 725 calories. (725 calories / 9 calories/g ≈ 81 g of fat)
Carbohydrates: Remaining calories. 2900 total calories – 600 protein calories – 725 fat calories = 1575 calories. (1575 calories / 4 calories/g ≈ 394 g of carbohydrates)
Result for this example: Approximately 150g Protein, 394g Carbohydrates, and 81g Fat.
Important Considerations:
This calculator provides an estimation. Individual metabolic rates and responses can vary.
It's recommended to consult with a registered dietitian, nutritionist, or healthcare professional for personalized advice.
Adjust your intake based on how your body responds, your energy levels, and your progress towards your goals.
Focus on nutrient-dense whole foods to meet your macro targets.
function calculateMacros() {
var bodyWeight = parseFloat(document.getElementById("bodyWeight").value);
var activityLevel = document.getElementById("activityLevel").value;
var goal = document.getElementById("goal").value;
var resultMessageElement = document.getElementById("resultMessage");
resultMessageElement.textContent = ""; // Clear previous messages
if (isNaN(bodyWeight) || bodyWeight targetCalories * 0.40) { // If 40% is too much for target calories
proteinPercentage = 0.40; // Use 40% if target calories allow reasonable g/kg
if (proteinCaloriesHighEnd > targetCalories) proteinPercentage = targetCalories / 4 / bodyWeight; // Absolute max protein per kg
} else if (proteinCaloriesHighEnd > targetCalories * proteinPercentage) {
proteinPercentage = targetCalories * proteinPercentage / proteinCaloriesHighEnd; // Adjust percentage if high end is lower than target percentage
}
proteinGrams = targetCalories * proteinPercentage / 4;
fatGrams = targetCalories * fatPercentage / 9;
carbsGrams = (targetCalories – (proteinGrams * 4) – (fatGrams * 9)) / 4;
// Ensure carbs are not negative
if (carbsGrams 0) {
fatGrams = remainingCaloriesForCarbs / 9; // Use remaining calories for fat
carbsGrams = 0; // Set carbs to 0 if absolutely necessary
resultMessageElement.textContent += " Note: Fat intake increased and carbs are minimal to meet calorie targets.";
} else {
// This scenario is unlikely with reasonable inputs but handles extreme cases.
fatGrams = targetCalories / 9; // Just fat and protein
carbsGrams = 0;
proteinGrams = 0; // If target calories are only enough for fat
resultMessageElement.textContent = "Warning: Calorie target is very low, making balanced macros difficult.";
}
}
document.getElementById("proteinTarget").textContent = proteinGrams.toFixed(0);
document.getElementById("carbsTarget").textContent = carbsGrams.toFixed(0);
document.getElementById("fatTarget").textContent = fatGrams.toFixed(0);
}