How to Calculate Total Metabolic Rate

Total Metabolic Rate (TMR) Calculator

Sedentary (Little or no exercise) Lightly Active (Exercise 1-3 days/week) Moderately Active (Exercise 3-5 days/week) Very Active (Exercise 6-7 days/week) Extra Active (Hard exercise/Physical job)

Your Results

Basal Metabolic Rate (BMR)

0 kcal

Total Daily Energy Expenditure (TDEE/TMR)

0 kcal

function calculateTMR() { var gender = document.getElementById("tmr_gender").value; var age = parseFloat(document.getElementById("tmr_age").value); var weight = parseFloat(document.getElementById("tmr_weight").value); var height = parseFloat(document.getElementById("tmr_height").value); var activity = parseFloat(document.getElementById("tmr_activity").value); if (isNaN(age) || isNaN(weight) || isNaN(height)) { alert("Please enter valid numbers for age, weight, and height."); return; } var bmr = 0; // Mifflin-St Jeor Equation if (gender === "male") { bmr = (10 * weight) + (6.25 * height) – (5 * age) + 5; } else { bmr = (10 * weight) + (6.25 * height) – (5 * age) – 161; } var tmr = bmr * activity; document.getElementById("bmr_val").innerText = Math.round(bmr).toLocaleString() + " kcal"; document.getElementById("tmr_val").innerText = Math.round(tmr).toLocaleString() + " kcal"; var summary = "To maintain your current weight, you need approximately " + Math.round(tmr).toLocaleString() + " calories per day. To lose weight (0.5kg/week), aim for " + Math.round(tmr – 500).toLocaleString() + " calories."; document.getElementById("tmr_summary").innerText = summary; document.getElementById("tmr_result_container").style.display = "block"; }

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How to Calculate Total Metabolic Rate

Understanding your Total Metabolic Rate (TMR), often referred to as Total Daily Energy Expenditure (TDEE), is the cornerstone of effective weight management and athletic performance. It represents the total number of calories your body burns in a 24-hour period based on your lifestyle and biology.

The Two-Step Formula

To calculate your TMR, we utilize a two-step process involving the Mifflin-St Jeor Equation, which is currently recognized as the most accurate standard for predicting energy expenditure in healthy individuals.

1. Step 1: Basal Metabolic Rate (BMR): This is the energy your body requires to perform basic life-sustaining functions at rest, such as breathing and cell production.
   • Men: (10 × weight in kg) + (6.25 × height in cm) – (5 × age) + 5
   • Women: (10 × weight in kg) + (6.25 × height in cm) – (5 × age) – 161
2. Step 2: Total Metabolic Rate (TMR): We multiply your BMR by a Physical Activity Level (PAL) factor to account for daily movement.

Activity Level Multipliers

Your lifestyle significantly impacts your TMR. The following multipliers are applied to your BMR:

• Sedentary (1.2): Little to no exercise, typically desk-bound work.
• Lightly Active (1.375): Light exercise or sports 1-3 days per week.
• Moderately Active (1.55): Moderate exercise or sports 3-5 days per week.
• Very Active (1.725): Hard exercise or sports 6-7 days per week.
• Extra Active (1.9): Very hard daily exercise or a highly physical job (e.g., construction).

Practical Example

Consider a 35-year-old male weighing 80kg, standing 180cm tall, who exercises moderately (3 times a week):

• BMR Calculation: (10 × 80) + (6.25 × 180) – (5 × 35) + 5 = 1,755 kcal
• TMR Calculation: 1,755 × 1.55 (Moderate Activity) = 2,720 kcal per day

In this scenario, consuming 2,720 calories per day will maintain his current weight. To lose weight, he should create a deficit (e.g., 2,220 kcal), and to gain weight, a surplus (e.g., 3,020 kcal).

Factors Influencing TMR

While the formula provides a strong estimate, individual results may vary due to:

• Muscle Mass: Muscle is more metabolically active than fat. Higher muscle mass increases BMR.
• Thermic Effect of Food (TEF): Digesting protein burns more energy than fats or carbohydrates.
• Hormonal Factors: Thyroid function plays a massive role in regulating metabolic speed.
• Climate: Extreme cold or heat can force the body to work harder to maintain internal temperature.