Your Basal Metabolic Rate (BMR) is the minimum number of calories your body needs to perform essential functions like breathing, circulation, and cell production at rest. It's the energy expenditure of your body in a completely rested state. Understanding your BMR is a crucial first step in managing your weight and optimizing your nutrition. It helps you determine the baseline calorie intake required to maintain your current weight, before accounting for physical activity.
This calculator uses the Mifflin-St Jeor equation, which is widely considered one of the most accurate formulas for estimating BMR. The equation differs slightly for men and women:
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
Simply enter your details below, and the calculator will provide an estimate of your BMR.
Male
Female
Your estimated Basal Metabolic Rate (BMR) is: — kcal/day
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 bmr = 0;
// Validate inputs
if (weight === "" || height === "" || age === "") {
document.getElementById("bmrValue").textContent = "Please fill in all fields.";
return;
}
var weightNum = parseFloat(weight);
var heightNum = parseFloat(height);
var ageNum = parseFloat(age);
if (isNaN(weightNum) || isNaN(heightNum) || isNaN(ageNum) || weightNum <= 0 || heightNum <= 0 || ageNum <= 0) {
document.getElementById("bmrValue").textContent = "Please enter valid positive numbers for all fields.";
return;
}
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("bmrValue").textContent = bmr.toFixed(2);
}