Your Basal Metabolic Rate (BMR) is the number of calories your body needs to perform basic life-sustaining functions at rest. This includes breathing, circulation, cell production, and nutrient processing. It's essentially the energy your body expends to keep you alive if you were to do nothing but rest all day.
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 burns more calories than fat tissue, even at rest.
Understanding your BMR is a crucial first step in managing your weight and overall health. It helps you determine a baseline calorie intake for weight maintenance, and with adjustments for activity level, can guide calorie goals for weight loss or gain.
We use the Mifflin-St Jeor equation, which is widely considered one of the most accurate formulas for estimating BMR:
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
Male
Female
function calculateBMR() {
var weightKg = parseFloat(document.getElementById("weightKg").value);
var heightCm = parseFloat(document.getElementById("heightCm").value);
var ageYears = parseFloat(document.getElementById("ageYears").value);
var gender = document.getElementById("gender").value;
var bmrResult = 0;
if (isNaN(weightKg) || isNaN(heightCm) || isNaN(ageYears) || weightKg <= 0 || heightCm <= 0 || ageYears <= 0) {
document.getElementById("result").innerHTML = "Please enter valid positive numbers for weight, height, and age.";
return;
}
if (gender === "male") {
bmrResult = (10 * weightKg) + (6.25 * heightCm) – (5 * ageYears) + 5;
} else { // female
bmrResult = (10 * weightKg) + (6.25 * heightCm) – (5 * ageYears) – 161;
}
document.getElementById("result").innerHTML = "Your estimated Basal Metabolic Rate (BMR) is: " + bmrResult.toFixed(2) + " calories per day.";
}