How Do You Calculate Basal Metabolic Rate

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Basal Metabolic Rate (BMR) Calculator

Basal Metabolic Rate (BMR) is the number of calories your body needs to perform basic, life-sustaining functions at rest. These functions include breathing, circulation, cell production, nutrient processing, and temperature regulation. Your BMR accounts for the largest portion of your daily calorie expenditure.

Several factors influence your BMR, including age, sex, weight, height, and body composition (muscle mass vs. fat mass). A higher muscle mass generally leads to a higher BMR because muscle tissue is metabolically more active than fat tissue.

The most commonly used formulas for calculating BMR are the Harris-Benedict Equation (revised) and the Mifflin-St Jeor Equation. The Mifflin-St Jeor Equation is generally considered more accurate for most people.

Male Female
function calculateBMR() { var gender = document.getElementById("gender").value; var weight = document.getElementById("weight").value; var height = document.getElementById("height").value; var age = document.getElementById("age").value; var weightNum = parseFloat(weight); var heightNum = parseFloat(height); var ageNum = parseFloat(age); var bmr = 0; if (isNaN(weightNum) || isNaN(heightNum) || isNaN(ageNum) || weightNum <= 0 || heightNum <= 0 || ageNum <= 0) { document.getElementById("bmrResult").innerHTML = "Please enter valid positive numbers for all fields."; return; } // Using Mifflin-St Jeor Equation if (gender === "male") { bmr = (10 * weightNum) + (6.25 * heightNum) – (5 * ageNum) + 5; } else { // female bmr = (10 * weightNum) + (6.25 * heightNum) – (5 * ageNum) – 161; } document.getElementById("bmrResult").innerHTML = "Your estimated Basal Metabolic Rate (BMR) is: " + bmr.toFixed(2) + " calories per day"; } .calculator-container { font-family: sans-serif; max-width: 500px; margin: 20px auto; padding: 20px; border: 1px solid #ccc; border-radius: 8px; box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1); } .calculator-container h2 { text-align: center; color: #333; margin-bottom: 15px; } .calculator-container p { color: #555; line-height: 1.6; margin-bottom: 15px; } .form-group { margin-bottom: 15px; } .form-group label { display: block; margin-bottom: 5px; font-weight: bold; color: #444; } .form-group input[type="number"], .form-group select { width: 100%; padding: 10px; border: 1px solid #ccc; border-radius: 4px; box-sizing: border-box; /* Ensures padding doesn't affect width */ } button { display: block; width: 100%; padding: 12px; background-color: #007bff; color: white; border: none; border-radius: 4px; font-size: 16px; cursor: pointer; transition: background-color 0.3s ease; } button:hover { background-color: #0056b3; } .result-container { margin-top: 20px; padding: 15px; background-color: #e9ecef; border: 1px solid #ced4da; border-radius: 4px; text-align: center; } .result-container p { margin: 0; color: #333; font-size: 1.1em; } .result-container strong { color: #007bff; } .error { color: #dc3545 !important; font-weight: bold; }

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