Calculate your TDEE (Total Daily Energy Expenditure)
Metric (kg, cm)
Imperial (lbs, inches)
Sedentary (little or no exercise)
Lightly Active (light exercise 1-3 days/week)
Moderately Active (moderate exercise 3-5 days/week)
Very Active (hard exercise 6-7 days/week)
Super Active (very hard exercise & physical job)
Please enter valid values for all fields.
Your Results
Basal Metabolic Rate (BMR):0
Daily Calories to Maintain Weight:0
Note: This is your estimated Total Daily Energy Expenditure. To lose weight, aim for a deficit (typically 500 kcal less).
function updateTMRLabels() {
var unitSystem = document.getElementById('tmr_unit_system').value;
var weightLabel = document.getElementById('label_weight');
var heightLabel = document.getElementById('label_height');
var weightInput = document.getElementById('tmr_weight');
var heightInput = document.getElementById('tmr_height');
if (unitSystem === 'imperial') {
weightLabel.innerText = "Weight (lbs)";
heightLabel.innerText = "Height (inches)";
weightInput.placeholder = "e.g., 160";
heightInput.placeholder = "e.g., 70 (5'10\" is 70)";
} else {
weightLabel.innerText = "Weight (kg)";
heightLabel.innerText = "Height (cm)";
weightInput.placeholder = "e.g., 70";
heightInput.placeholder = "e.g., 175";
}
}
function calculateTotalMetabolicRate() {
// 1. Get input values
var unitSystem = document.getElementById('tmr_unit_system').value;
var age = parseFloat(document.getElementById('tmr_age').value);
var weightInput = parseFloat(document.getElementById('tmr_weight').value);
var heightInput = parseFloat(document.getElementById('tmr_height').value);
var activityMultiplier = parseFloat(document.getElementById('tmr_activity').value);
var genderMale = document.getElementById('tmr_gender_male').checked;
// 2. Error handling
var errorDiv = document.getElementById('tmr_error');
var resultDiv = document.getElementById('tmr_result_display');
if (isNaN(age) || isNaN(weightInput) || isNaN(heightInput) || age <= 0 || weightInput <= 0 || heightInput <= 0) {
errorDiv.style.display = "block";
resultDiv.style.display = "none";
return;
}
errorDiv.style.display = "none";
// 3. Convert units to Metric for Calculation (Mifflin-St Jeor uses kg and cm)
var weightKg = weightInput;
var heightCm = heightInput;
if (unitSystem === 'imperial') {
// lbs to kg
weightKg = weightInput * 0.453592;
// inches to cm
heightCm = heightInput * 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 (genderMale) {
bmr = (10 * weightKg) + (6.25 * heightCm) – (5 * age) + 5;
} else {
bmr = (10 * weightKg) + (6.25 * heightCm) – (5 * age) – 161;
}
// 5. Calculate TMR (BMR * Activity)
var tmr = bmr * activityMultiplier;
// 6. Display Results
document.getElementById('val_bmr').innerHTML = Math.round(bmr) + " kcal/day";
document.getElementById('val_tmr').innerHTML = Math.round(tmr) + " kcal/day";
resultDiv.style.display = "block";
}
Understanding Your Total Metabolic Rate
The Total Metabolic Rate (TMR), often referred to as Total Daily Energy Expenditure (TDEE), represents the total number of calories your body burns in a 24-hour period. Unlike simpler metrics that only account for resting energy, TMR combines your baseline biological needs with the energy expended during physical activity and food digestion.
Knowing your TMR is the cornerstone of any effective nutrition plan. Whether your goal is to lose fat, build muscle, or maintain your current physique, the TMR serves as the mathematical "break-even" point for your daily caloric intake.
The 3 Components of Total Metabolic Rate
Your daily energy expenditure is composed of three distinct factors:
Basal Metabolic Rate (BMR): This accounts for 60-75% of your total burn. It is the energy required to keep your vital organs functioning (breathing, circulating blood, cell production) while you are completely at rest.
Thermic Effect of Food (TEF): Approximately 10% of your energy is used to digest, absorb, and metabolize the food you eat. Protein typically has a higher thermic effect than fats or carbohydrates.
Physical Activity Level (PAL): This is the most variable component, ranging from 15-30% or more. It includes both deliberate exercise (EAT – Exercise Activity Thermogenesis) and non-exercise movement (NEAT – Non-Exercise Activity Thermogenesis), such as walking to the car or fidgeting.
How TMR is Calculated
This calculator utilizes the Mifflin-St Jeor equation, widely considered by clinical nutritionists to be the most accurate standard for estimating calorie needs in the general population.
The process works in two steps:
First, we calculate your BMR based on your gender, age, height, and weight.
Example: A 30-year-old male, 180cm tall, weighing 80kg has a BMR of approximately 1,770 kcal.
Second, we apply an Activity Multiplier to account for your lifestyle:
Sedentary (x 1.2): Desk job, little to no exercise.
Lightly Active (x 1.375): Light exercise 1-3 days/week.
Moderately Active (x 1.55): Moderate sports 3-5 days/week.
Very Active (x 1.725): Hard exercise 6-7 days/week.
Extra Active (x 1.9): Very hard exercise and a physical job.
Using TMR for Weight Management
Once you have calculated your Total Metabolic Rate, you can adjust your intake based on your goals:
Weight Loss: Aim for a caloric deficit. Subtracting 500 calories from your TMR typically results in losing about 0.5 kg (1 lb) per week.
Maintenance: Eat an amount of calories equal to your TMR.
Weight Gain (Muscle Building): Aim for a caloric surplus. Adding 250-500 calories above your TMR provides the energy required to synthesize new muscle tissue.
Frequently Asked Questions
Does muscle mass affect TMR?
Yes. Muscle tissue is more metabolically active than fat tissue. An individual with a higher muscle mass will have a higher BMR and TMR than someone of the same weight with higher body fat.
How often should I recalculate?
You should recalculate your metabolic rate whenever your weight changes significantly (more than 5 lbs or 2-3 kg), or if your activity level changes (e.g., starting a new job or workout routine).