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Professional BMR & TDEE Calculator

Calculate your Basal Metabolic Rate using the Mifflin-St Jeor Equation

Male Female
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 Basal Metabolic Rate (BMR):
0 Calories/day
Total Daily Energy Expenditure (TDEE):
0 Calories/day

Note: TDEE is the number of calories you need to maintain your current weight based on your activity level.

Understanding Your BMR and TDEE

Basal Metabolic Rate (BMR) is the minimum number of calories your body requires to perform basic life-sustaining functions while at rest, such as breathing, circulation, and cell production. It accounts for about 60% to 75% of your total daily energy expenditure.

The Mifflin-St Jeor Equation

This calculator utilizes the Mifflin-St Jeor equation, currently considered the most accurate standard for calculating BMR in healthy adults. The formulas are as follows:

  • 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

How to Use These Results

Your TDEE (Total Daily Energy Expenditure) is the most important number for weight management:

  • Maintenance: Eat your TDEE calories.
  • Weight Loss: Aim for a deficit (typically 500 calories below TDEE).
  • Muscle Gain: Aim for a surplus (typically 250-500 calories above TDEE).

Example Calculation

A 35-year-old male weighing 80kg at 180cm height:

BMR = (10 × 80) + (6.25 × 180) – (5 × 35) + 5
BMR = 800 + 1125 – 175 + 5 = 1,755 Calories/day

If he is "Moderately Active" (1.55 multiplier), his TDEE would be: 1,755 × 1.55 = 2,720 Calories/day.

function calculateBMR() { var weight = parseFloat(document.getElementById("bmrWeight").value); var height = parseFloat(document.getElementById("bmrHeight").value); var age = parseFloat(document.getElementById("bmrAge").value); var gender = document.getElementById("bmrGender").value; var activity = parseFloat(document.getElementById("bmrActivity").value); var resultArea = document.getElementById("bmrResultArea"); var bmrOutput = document.getElementById("bmrOutput"); var tdeeOutput = document.getElementById("tdeeOutput"); if (isNaN(weight) || isNaN(height) || isNaN(age) || weight <= 0 || height <= 0 || age <= 0) { alert("Please enter valid positive numbers for weight, height, and age."); return; } var bmr = 0; if (gender === "male") { // Mifflin-St Jeor for Men bmr = (10 * weight) + (6.25 * height) – (5 * age) + 5; } else { // Mifflin-St Jeor for Women bmr = (10 * weight) + (6.25 * height) – (5 * age) – 161; } var tdee = bmr * activity; bmrOutput.innerHTML = Math.round(bmr).toLocaleString(); tdeeOutput.innerHTML = Math.round(tdee).toLocaleString(); resultArea.style.display = "block"; resultArea.scrollIntoView({ behavior: 'smooth', block: 'nearest' }); }

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