Basal Metabolic Rate (BMR) Calculator
What is Basal Metabolic Rate (BMR)?
Basal Metabolic Rate (BMR) represents the minimum number of calories your body needs to perform its essential functions while at rest. These functions include breathing, circulation, cell production, nutrient processing, and maintaining body temperature. Essentially, it's the energy your body burns just to stay alive when you're not doing any physical activity.
Your BMR is influenced by several factors, including your gender, age, weight, and height. Generally, men tend to have a higher BMR than women due to higher muscle mass. As you age, your BMR typically decreases. Larger body mass requires more energy to maintain, thus leading to a higher BMR.
Understanding your BMR is a crucial first step in managing your weight and dietary intake. It forms the baseline for calculating your Total Daily Energy Expenditure (TDEE), which is the total number of calories you burn in a day, including physical activity.
This calculator uses 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
Enter your details above to estimate your Basal Metabolic Rate in kilocalories (kcal) per day.
function calculateBMR() {
var gender = document.getElementById("gender").value;
var weightKg = parseFloat(document.getElementById("weightKg").value);
var heightCm = parseFloat(document.getElementById("heightCm").value);
var age = parseFloat(document.getElementById("age").value);
var resultDiv = document.getElementById("result");
var bmr = 0;
if (isNaN(weightKg) || isNaN(heightCm) || isNaN(age) || weightKg <= 0 || heightCm <= 0 || age <= 0) {
resultDiv.innerHTML = "Please enter valid positive numbers for weight, height, and age.";
return;
}
if (gender === "male") {
bmr = (10 * weightKg) + (6.25 * heightCm) – (5 * age) + 5;
} else { // female
bmr = (10 * weightKg) + (6.25 * heightCm) – (5 * age) – 161;
}
if (bmr < 0) { // Ensure BMR is not negative, though unlikely with valid inputs
bmr = 0;
}
resultDiv.innerHTML = "Your estimated Basal Metabolic Rate (BMR) is:
" + bmr.toFixed(2) + " kcal/day";
}
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