Sedentary (Office job, little exercise)
Lightly Active (Exercise 1-3 days/week)
Moderately Active (Exercise 3-5 days/week)
Very Active (Exercise 6-7 days/week)
Extra Active (Physical job or 2x training)
Lose 1 lb per week (Recommended)
Lose 2 lbs per week (Aggressive)
Maintain Weight
Gain 0.5 lb per week (Lean Bulk)
Gain 1 lb per week
Daily Calorie Target
2,500
Calories / Day
Basal Metabolic Rate (BMR):1,800
Maintenance Calories (TDEE):2,500
Protein
180g
Moderate (30%)
Fats
80g
Healthy Fats (35%)
Carbs
250g
Fuel (35%)
Understanding Your TDEE and Macros
Calculating your Total Daily Energy Expenditure (TDEE) is the fundamental first step in any fitness journey. Whether you are looking to lose body fat, build muscle, or simply maintain your current physique, understanding the math behind your metabolism is crucial. This calculator uses the Mifflin-St Jeor equation, widely considered the most accurate formula for estimating calorie needs.
What is TDEE?
TDEE stands for Total Daily Energy Expenditure. It represents the total number of calories your body burns in a 24-hour period. It is composed of two main parts:
BMR (Basal Metabolic Rate): The calories your body burns just to stay alive (breathing, circulating blood, cell production) at complete rest.
Activity Expenditure: The calories burned through exercise, walking, your job, and Non-Exercise Activity Thermogenesis (NEAT).
If you eat exactly your TDEE, your weight will remain the same. To lose weight, you must eat below this number (a calorie deficit). To gain muscle, you typically need to eat slightly above this number (a calorie surplus).
How We Calculate Your Macros
While calories determine your weight, macronutrients (macros) determine your body composition. This calculator provides a balanced "Moderate Carb" split, which is effective for most people starting their journey:
Protein: Essential for muscle repair and retention. We prioritize protein to help you keep muscle while losing fat.
Fats: Vital for hormonal health and nutrient absorption.
Carbohydrates: The body's primary fuel source for high-intensity activity and brain function.
Tips for Success
1. Be Honest About Activity: Most people overestimate how active they are. If you have a desk job and lift weights 3 times a week, select "Lightly Active," not "Moderately Active."
2. Weigh Your Food: To hit these macro targets accurately, using a food scale and a tracking app is highly recommended.
3. Monitor and Adjust: Calculators are estimates. If you don't see weight changes after 2 weeks, adjust your daily intake by +/- 200 calories accordingly.
function calculateTDEE() {
// 1. Get Input Values
var age = parseFloat(document.getElementById('age').value);
var weightLbs = parseFloat(document.getElementById('weight').value);
var heightFt = parseFloat(document.getElementById('heightFt').value);
var heightIn = parseFloat(document.getElementById('heightIn').value);
var activityMultiplier = parseFloat(document.getElementById('activity').value);
var goalAdjustment = parseFloat(document.getElementById('goal').value);
// Get Gender Radio Value
var gender = 'male';
var genderRadios = document.getElementsByName('gender');
for(var i = 0; i < genderRadios.length; i++) {
if(genderRadios[i].checked) {
gender = genderRadios[i].value;
}
}
// 2. Validation
if (isNaN(age) || isNaN(weightLbs) || isNaN(heightFt) || isNaN(heightIn)) {
alert("Please enter valid numbers for Age, Weight, and Height.");
return;
}
// 3. Convert Units (Imperial to Metric)
var weightKg = weightLbs / 2.20462;
var heightCm = ((heightFt * 12) + heightIn) * 2.54;
// 4. Calculate BMR (Mifflin-St Jeor Equation)
// Men: (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
// Women: (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161
var bmr = 0;
if (gender === 'male') {
bmr = (10 * weightKg) + (6.25 * heightCm) – (5 * age) + 5;
} else {
bmr = (10 * weightKg) + (6.25 * heightCm) – (5 * age) – 161;
}
// 5. Calculate TDEE and Goal Calories
var tdee = bmr * activityMultiplier;
var targetCalories = tdee + goalAdjustment;
// Safety check for very low calories
if (targetCalories < 1200) {
targetCalories = 1200; // Unsafe floor
}
// 6. Calculate Macros (Split: 30% Protein, 35% Fat, 35% Carb – Balanced Approach)
// Protein: 4 cal/g, Fat: 9 cal/g, Carb: 4 cal/g
var proteinCals = targetCalories * 0.30;
var fatCals = targetCalories * 0.35;
var carbCals = targetCalories * 0.35;
var proteinGrams = Math.round(proteinCals / 4);
var fatGrams = Math.round(fatCals / 9);
var carbGrams = Math.round(carbCals / 4);
// 7. Display Results
document.getElementById('resultsArea').style.display = 'block';
// Format numbers with commas
document.getElementById('dailyCalories').innerText = Math.round(targetCalories).toLocaleString();
document.getElementById('bmrValue').innerText = Math.round(bmr).toLocaleString() + ' kcal';
document.getElementById('tdeeValue').innerText = Math.round(tdee).toLocaleString() + ' kcal';
document.getElementById('proteinGrams').innerText = proteinGrams + 'g';
document.getElementById('fatGrams').innerText = fatGrams + 'g';
document.getElementById('carbGrams').innerText = carbGrams + 'g';
// Scroll to results
document.getElementById('resultsArea').scrollIntoView({behavior: 'smooth'});
}