Calculate your daily protein, carbohydrate, and fat intake for effective weight loss.
kg
cm
years
Male
Female
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)
kg per week
Your Daily Macronutrient Goals for Weight Loss
Calories:– kcal
Protein:– g
Carbohydrates:– g
Fat:– g
Understanding Macronutrients and Weight Loss
Achieving sustainable weight loss involves more than just reducing calorie intake. It requires understanding and balancing your macronutrients – protein, carbohydrates, and fats. Macronutrients are the nutrients your body needs in large amounts to provide energy and support various bodily functions.
What are Macronutrients?
Protein: Essential for building and repairing tissues, producing enzymes and hormones, and supporting immune function. Protein is also highly satiating, meaning it helps you feel fuller for longer, which can be crucial for managing hunger during weight loss.
Carbohydrates: The body's primary source of energy. They are broken down into glucose, which fuels your brain and muscles. Complex carbohydrates (found in whole grains, vegetables, and fruits) are preferable for sustained energy release.
Fats: Crucial for hormone production, nutrient absorption, and cell function. Healthy fats (found in avocados, nuts, seeds, and olive oil) are vital for overall health.
Calculating Your Needs: The Science Behind the Macros
This calculator uses a multi-step process to estimate your daily macronutrient needs for weight loss.
1. Basal Metabolic Rate (BMR):
Your BMR is the number of calories your body burns at rest to maintain basic functions like breathing, circulation, and cell production. The Mifflin-St Jeor equation is widely considered one of the most accurate for estimating BMR:
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
2. Total Daily Energy Expenditure (TDEE):
Your TDEE is the total number of calories you burn in a day, including your BMR and calories burned through physical activity. It's calculated by multiplying your BMR by an activity factor:
TDEE = BMR * Activity Factor
Activity Factors:
Sedentary: 1.2
Lightly active: 1.375
Moderately active: 1.55
Very active: 1.725
Extra active: 1.9
3. Calorie Deficit for Weight Loss:
To lose weight, you need to consume fewer calories than your TDEE, creating a calorie deficit. A deficit of 500-1000 calories per day typically results in a weight loss of about 0.5-1 kg per week. This calculator aims for a deficit based on your desired weekly weight loss. Approximately 7700 calories equal 1 kg of body fat.
Once your target calorie intake is determined, macros are distributed based on common, effective ratios for weight loss:
Protein: Aim for 1.6 to 2.2 grams of protein per kilogram of body weight. This supports muscle maintenance during calorie restriction and aids satiety.
Fat: Typically set between 20% to 30% of total daily calories. Healthy fats are essential for hormone function. (1 gram of fat = 9 calories)
Carbohydrates: The remaining calories are filled with carbohydrates. (1 gram of carbohydrate = 4 calories)
The calculator prioritizes protein and fat intake and then allocates the rest to carbohydrates to meet your calorie target.
Disclaimer:
This calculator provides an estimate based on common formulas. Individual metabolic rates and responses to diet can vary. For personalized advice, consult a registered dietitian, nutritionist, or healthcare professional.
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 = document.getElementById("activityLevel").value;
var weightLossRate = parseFloat(document.getElementById("weightLossRate").value);
var bmr = 0;
if (isNaN(weight) || isNaN(height) || isNaN(age)) {
alert("Please enter valid numbers for weight, height, and age.");
return;
}
if (weight <= 0 || height <= 0 || age <= 0) {
alert("Weight, height, and age must be positive values.");
return;
}
// Calculate BMR using Mifflin-St Jeor Equation
if (gender === "male") {
bmr = (10 * weight) + (6.25 * height) – (5 * age) + 5;
} else { // female
bmr = (10 * weight) + (6.25 * height) – (5 * age) – 161;
}
var activityMultiplier = 0;
switch (activityLevel) {
case "sedentary":
activityMultiplier = 1.2;
break;
case "light":
activityMultiplier = 1.375;
break;
case "moderate":
activityMultiplier = 1.55;
break;
case "very_active":
activityMultiplier = 1.725;
break;
case "extra_active":
activityMultiplier = 1.9;
break;
default:
activityMultiplier = 1.2; // Default to sedentary
}
var tdee = bmr * activityMultiplier;
// Calculate calorie deficit for weight loss
var caloriesPerKgFat = 7700;
var dailyCalorieDeficit = 0;
if (isNaN(weightLossRate) || weightLossRate < 0) {
alert("Please enter a valid non-negative number for desired weekly weight loss.");
weightLossRate = 0.5; // Default to 0.5kg/week if invalid
}
dailyCalorieDeficit = (weightLossRate * caloriesPerKgFat) / 7;
var dailyCalorieTarget = tdee – dailyCalorieDeficit;
// Ensure calorie target is not excessively low
if (dailyCalorieTarget < 1200) { // A common minimum guideline for women
dailyCalorieTarget = 1200;
}
if (dailyCalorieTarget < 1500 && gender === "male") { // A common minimum guideline for men
dailyCalorieTarget = 1500;
}
// Macronutrient Calculations
var proteinGrams = weight * 1.8; // Using 1.8g/kg as a middle ground for weight loss
var proteinCalories = proteinGrams * 4;
var fatPercentage = 0.25; // Aiming for 25% of calories from fat
var fatCalories = dailyCalorieTarget * fatPercentage;
var fatGrams = fatCalories / 9;
var carbCalories = dailyCalorieTarget – proteinCalories – fatCalories;
var carbGrams = carbCalories / 4;
// Ensure no macro is negative
if (proteinGrams < 0) proteinGrams = 0;
if (fatGrams < 0) fatGrams = 0;
if (carbGrams < 0) carbGrams = 0;
if (dailyCalorieTarget < 0) dailyCalorieTarget = 0;
document.getElementById("dailyCalories").textContent = dailyCalorieTarget.toFixed(0);
document.getElementById("dailyProtein").textContent = proteinGrams.toFixed(0);
document.getElementById("dailyCarbs").textContent = carbGrams.toFixed(0);
document.getElementById("dailyFat").textContent = fatGrams.toFixed(0);
}