Sedentary (little or 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 or 2x training)
Understanding Your Daily Calorie and Macro Needs
This calculator helps you estimate your daily calorie and macronutrient (protein, carbohydrates, and fats) requirements based on your personal attributes and activity level. Understanding these numbers is crucial for managing weight, building muscle, or simply maintaining a healthy lifestyle.
Basal Metabolic Rate (BMR)
The calculation begins with determining your Basal Metabolic Rate (BMR), which is the number of calories your body burns at rest to maintain basic functions like breathing, circulation, and cell production. We use the Mifflin-St Jeor equation, which is widely considered one of the most accurate formulas for BMR estimation:
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
Note: weight is in kilograms (kg), height is in centimeters (cm), and age is in years.
Total Daily Energy Expenditure (TDEE)
Your BMR is then adjusted for your daily physical activity level to estimate your Total Daily Energy Expenditure (TDEE). This is the total number of calories you burn in a day, including your BMR and the calories burned through all your activities. The activity multipliers used are:
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
TDEE represents your maintenance calorie level – the calories you need to consume to maintain your current weight.
Macronutrient Breakdown
Once your TDEE is calculated, we can break it down into recommended ranges for the three main macronutrients: protein, carbohydrates, and fats. These are general guidelines and can be adjusted based on individual goals (e.g., muscle gain, fat loss, endurance performance).
General Recommendations (as a percentage of TDEE):
Protein: 20-30% (Essential for muscle repair, growth, and satiety. 1 gram of protein = 4 calories)
Fats: 20-30% (Important for hormone production, nutrient absorption, and energy. 1 gram of fat = 9 calories)
Carbohydrates: 40-60% (The body's primary source of energy. 1 gram of carbohydrates = 4 calories)
This calculator provides a common distribution: 30% Protein, 40% Carbohydrates, and 30% Fat. You can adjust these percentages based on your specific dietary approach or consult with a nutritionist.
How to Use This Calculator
Enter your current Weight in kilograms (kg).
Enter your Height in centimeters (cm).
Enter your Age in years.
Select your Gender.
Choose your Activity Level from the dropdown menu, selecting the option that best describes your typical weekly exercise and lifestyle.
Click "Calculate Daily Needs".
The results will provide your estimated daily calorie needs and the corresponding grams of protein, carbohydrates, and fats required to meet those targets. Remember, these are estimates, and individual needs can vary.
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 resultDiv = document.getElementById("result");
resultDiv.innerHTML = "; // Clear previous results
if (isNaN(weight) || isNaN(height) || isNaN(age) || weight <= 0 || height <= 0 || age <= 0) {
resultDiv.innerHTML = 'Please enter valid positive numbers for weight, height, and age.';
return;
}
var bmr = 0;
if (gender === "male") {
bmr = (10 * weight) + (6.25 * height) – (5 * age) + 5;
} else { // female
bmr = (10 * weight) + (6.25 * height) – (5 * age) – 161;
}
var tdee = bmr * activityLevel;
// Macronutrient calculations (e.g., 30% Protein, 40% Carbs, 30% Fat)
var proteinCalories = tdee * 0.30;
var carbCalories = tdee * 0.40;
var fatCalories = tdee * 0.30;
var proteinGrams = proteinCalories / 4;
var carbGrams = carbCalories / 4;
var fatGrams = fatCalories / 9;
resultDiv.innerHTML =
'Your Estimated Daily Needs:' +
'' + tdee.toFixed(0) + ' Kcal Total' +
'' + proteinGrams.toFixed(0) + 'g Protein' +
'' + carbGrams.toFixed(0) + 'g Carbohydrates' +
'' + fatGrams.toFixed(0) + 'g Fat';
}