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 a week)
Extra Active (very hard exercise/sports & physical job)
Lose Weight
Maintain Weight
Gain Muscle
Your Macro Targets
Please enter your details above and click "Calculate My Macros".
Understanding Macronutrients and Your Macro Diet Calculator
A macro diet, short for macronutrient diet, focuses on tracking the intake of the three primary macronutrients: carbohydrates, proteins, and fats. These are the nutrients your body needs in large amounts to provide energy and support bodily functions. By understanding and managing your intake of these macros, you can effectively work towards specific fitness and health goals, such as weight loss, muscle gain, or maintaining your current physique.
How the Macro Diet Calculator Works
This calculator uses a common formula to estimate your Total Daily Energy Expenditure (TDEE) and then adjusts it based on your weight goal to provide personalized macronutrient targets.
Basal Metabolic Rate (BMR): First, your BMR is calculated. This is the number of calories your body burns at rest to maintain basic functions. The calculator uses the Mifflin-St Jeor equation, which is considered one of the most accurate:
For men: BMR = (10 * weight in kg) + (6.25 * height in cm) – (5 * age in years) + 5
For women: BMR = (10 * weight in kg) + (6.25 * height in cm) – (5 * age in years) – 161
Total Daily Energy Expenditure (TDEE): Your BMR is then multiplied by an activity factor to estimate your TDEE – the total calories you burn daily, including exercise and daily activities.
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
Calorie Adjustment for Goal:
Weight Loss: To lose approximately 0.5 kg (1.1 lbs) per week, a deficit of about 500 calories per day is needed. The calculator subtracts calories based on your desired weekly weight change rate (1 kg of fat is roughly 7700 calories).
Weight Gain: To gain muscle, a surplus of about 250-500 calories per day is recommended. The calculator adds calories based on your desired weekly weight change rate.
Maintenance: TDEE is used directly with no calorie adjustment.
Macronutrient Breakdown: Once the target daily calorie intake is determined, it's divided among protein, carbohydrates, and fats. The distribution can vary, but common recommendations are:
Protein: Generally set at 1.6-2.2 grams per kilogram of body weight. This is crucial for muscle repair and growth. (4 calories per gram)
Fats: Typically set at 20-30% of total daily calories. Healthy fats are essential for hormone production and nutrient absorption. (9 calories per gram)
Carbohydrates: The remaining calories are allocated to carbohydrates, which are the body's primary source of energy. (4 calories per gram)
The calculator prioritizes protein and fat intake based on these guidelines and fills the remainder with carbohydrates.
Why Track Macros?
Tracking macros offers a more nuanced approach to nutrition than simply counting calories. It ensures you're consuming adequate protein for muscle maintenance and growth, healthy fats for hormonal balance, and carbohydrates for energy, all while managing your overall calorie intake to achieve your specific weight goals. This method can lead to better body composition changes and a more sustainable approach to healthy eating.
Disclaimer: This calculator provides estimations based on common formulas. Consult with a healthcare professional or registered dietitian for personalized dietary advice.
function calculateMacros() {
var weight = parseFloat(document.getElementById("weight").value);
var height = parseFloat(document.getElementById("height").value);
var age = parseFloat(document.getElementById("age").value);
var gender = document.getElementById("gender").value;
var activityLevel = parseFloat(document.getElementById("activityLevel").value);
var goal = document.getElementById("goal").value;
var weightChangeRate = parseFloat(document.getElementById("weightChangeRate").value);
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
// — Input Validation —
if (isNaN(weight) || weight <= 0 ||
isNaN(height) || height <= 0 ||
isNaN(age) || age <= 0 ||
isNaN(weightChangeRate) || weightChangeRate <= 0) {
resultDiv.innerHTML = "Please enter valid positive numbers for weight, height, age, and desired weekly weight change.";
return;
}
// — BMR Calculation (Mifflin-St Jeor Equation) —
var bmr;
if (gender === "male") {
bmr = (10 * weight) + (6.25 * height) – (5 * age) + 5;
} else { // female
bmr = (10 * weight) + (6.25 * height) – (5 * age) – 161;
}
// — TDEE Calculation —
var tdee = bmr * activityLevel;
// — Calorie Adjustment based on Goal —
var calorieTarget;
var caloriesPerKg = 7700; // Approximate calories in 1 kg of fat
if (goal === "lose") {
// Target deficit: 500 calories/day for 0.5kg/week loss
// Adjust deficit based on desired weightChangeRate
var dailyDeficit = weightChangeRate * caloriesPerKg / 7;
calorieTarget = tdee – dailyDeficit;
} else if (goal === "gain") {
// Target surplus: 250-500 calories/day for muscle gain
// Adjust surplus based on desired weightChangeRate
var dailySurplus = weightChangeRate * caloriesPerKg / 7;
calorieTarget = tdee + dailySurplus;
} else { // maintain
calorieTarget = tdee;
}
// Ensure calorie target is not unrealistically low or high
if (calorieTarget < 1200) { // Minimum generally recommended calories for women
calorieTarget = 1200;
}
if (gender === "male" && calorieTarget < 1500) { // Minimum generally recommended calories for men
calorieTarget = 1500;
}
// — Macronutrient Calculation —
var proteinGrams;
var fatPercentage;
var proteinPerKg = 1.6; // Lower end of recommended range (1.6-2.2 g/kg)
if (goal === "gain") {
proteinPerKg = 2.0; // Higher end for muscle gain
}
proteinGrams = weight * proteinPerKg;
var proteinCalories = proteinGrams * 4;
// Fat percentage: ~25-30% of calories, can adjust slightly based on goal
if (goal === "lose") {
fatPercentage = 0.25; // Slightly lower fat for weight loss can help with deficit
} else {
fatPercentage = 0.30; // Standard or slightly higher for maintenance/gain
}
var fatCalories = calorieTarget * fatPercentage;
var fatGrams = fatCalories / 9;
// Carbohydrates fill the remaining calories
var carbCalories = calorieTarget – proteinCalories – fatCalories;
var carbGrams = carbCalories / 4;
// — Display Results —
resultDiv.innerHTML =
"Daily Calorie Target: " + Math.round(calorieTarget) + " kcal" +
"Protein: " + Math.round(proteinGrams) + " g (approx. " + Math.round((proteinCalories / calorieTarget) * 100) + "%)" +
"Fats: " + Math.round(fatGrams) + " g (approx. " + Math.round(fatPercentage * 100) + "%)" +
"Carbohydrates: " + Math.round(carbGrams) + " g (approx. " + Math.round((carbCalories / calorieTarget) * 100) + "%)";
}