Estimate your Basal Metabolic Rate (BMR), the number of calories your body needs to perform basic life-sustaining functions at rest.
Male
Female
Your BMR will appear here.
What is Basal Metabolic Rate (BMR)?
Basal Metabolic Rate (BMR) is the minimum amount of energy your body needs to maintain basic physiological functions while at rest. These functions include breathing, circulation, cell production, nutrient processing, protein synthesis, and the functioning of the nervous system. It's essentially the calories your body burns just to stay alive, even if you were to spend the entire day lying still.
Understanding your BMR is the first step in understanding your total daily energy expenditure (TDEE). Your TDEE is your BMR plus the calories you burn through physical activity and the thermic effect of food (the calories burned digesting and absorbing food). Knowing your BMR can help you set realistic goals for weight management, whether you are trying to lose weight, gain muscle, or maintain your current weight.
The most commonly used formulas for calculating BMR are the Harris-Benedict Equation and the Mifflin-St Jeor Equation. This calculator uses the Mifflin-St Jeor Equation, which is generally considered more accurate for most people.
Mifflin-St Jeor Equation:
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
Note: BMR is an estimate. Individual metabolic rates can vary due to genetics, body composition (muscle mass vs. fat mass), and other factors. For the most accurate assessment, consult with a healthcare professional or a registered dietitian.
function calculateBMR() {
var gender = document.getElementById("gender").value;
var weight = parseFloat(document.getElementById("weight").value);
var height = parseFloat(document.getElementById("height").value);
var age = parseFloat(document.getElementById("age").value);
var bmrResult = document.getElementById("result");
if (isNaN(weight) || isNaN(height) || isNaN(age) || weight <= 0 || height <= 0 || age <= 0) {
bmrResult.innerHTML = "Please enter valid positive numbers for weight, height, and age.";
return;
}
var bmr;
if (gender === "male") {
bmr = (10 * weight) + (6.25 * height) – (5 * age) + 5;
} else { // female
bmr = (10 * weight) + (6.25 * height) – (5 * age) – 161;
}
// Display the result with units
bmrResult.innerHTML = "Your estimated BMR is: " + bmr.toFixed(2) + " calories per day.";
}