Basal Metabolic Rate (BMR) Calculator for Weight Loss
Your Basal Metabolic Rate (BMR) is the number of calories your body needs to perform basic life-sustaining functions at rest. Understanding your BMR is crucial for effective weight loss, as it forms the foundation of your daily calorie needs. By calculating your BMR, you can then determine a calorie deficit that promotes fat loss without severely impacting your health or metabolism.
Male
Female
function calculateBMR() {
var gender = document.getElementById("gender").value;
var weightKg = parseFloat(document.getElementById("weightKg").value);
var heightCm = parseFloat(document.getElementById("heightCm").value);
var ageYears = parseFloat(document.getElementById("ageYears").value);
var bmr = 0;
if (isNaN(weightKg) || isNaN(heightCm) || isNaN(ageYears) || weightKg <= 0 || heightCm <= 0 || ageYears <= 0) {
document.getElementById("bmrResult").innerHTML = "Please enter valid positive numbers for weight, height, and age.";
document.getElementById("weightLossInfo").innerHTML = "";
return;
}
if (gender === "male") {
// Mifflin-St Jeor Equation for Men
bmr = (10 * weightKg) + (6.25 * heightCm) – (5 * ageYears) + 5;
} else {
// Mifflin-St Jeor Equation for Women
bmr = (10 * weightKg) + (6.25 * heightCm) – (5 * ageYears) – 161;
}
var resultHtml = "Your estimated Basal Metabolic Rate (BMR) is: " + bmr.toFixed(2) + " calories/day";
document.getElementById("bmrResult").innerHTML = resultHtml;
// Information for weight loss
var weightLossTarget = 0.5; // Target 0.5 kg of weight loss per week
var caloriesPerKgFat = 7700; // Approximate calories in 1 kg of fat
var dailyDeficit = weightLossTarget * caloriesPerKgFat / 7; // Daily calorie deficit needed
var weightLossInfoHtml = "To lose approximately " + weightLossTarget + " kg per week, you need to create a daily calorie deficit of about " + dailyDeficit.toFixed(0) + " calories. ";
weightLossInfoHtml += "This means your daily intake should ideally be around " + (bmr – dailyDeficit).toFixed(0) + " calories. ";
weightLossInfoHtml += "Remember to consult with a healthcare professional or a registered dietitian before making significant changes to your diet or exercise routine. ";
weightLossInfoHtml += "This calculator provides an estimate and does not account for individual metabolic variations or activity levels beyond BMR.";
document.getElementById("weightLossInfo").innerHTML = weightLossInfoHtml;
}
.bmi-calculator-container {
font-family: sans-serif;
border: 1px solid #ccc;
padding: 20px;
border-radius: 8px;
max-width: 500px;
margin: 20px auto;
background-color: #f9f9f9;
}
.bmi-calculator-container h2 {
text-align: center;
margin-bottom: 20px;
color: #333;
}
.bmi-calculator-container p {
font-size: 0.9em;
color: #555;
line-height: 1.5;
margin-bottom: 20px;
}
.calculator-inputs {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 15px;
margin-bottom: 20px;
}
.calculator-inputs label {
display: block;
margin-bottom: 5px;
font-weight: bold;
color: #444;
grid-column: 1 / 2; /* Align labels to the left column */
}
.calculator-inputs input[type="number"],
.calculator-inputs select {
width: 100%;
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
box-sizing: border-box; /* Include padding and border in the element's total width and height */
grid-column: 2 / 3; /* Align inputs to the right column */
}
.calculator-inputs select {
grid-column: 2 / 3;
}
.calculator-inputs button {
grid-column: 1 / 3; /* Span across both columns */
width: 100%;
padding: 12px 20px;
background-color: #5cb85c;
color: white;
border: none;
border-radius: 4px;
cursor: pointer;
font-size: 1em;
transition: background-color 0.3s ease;
}
.calculator-inputs button:hover {
background-color: #4cae4c;
}
.calculator-result {
margin-top: 20px;
padding: 15px;
background-color: #dff0d8;
border: 1px solid #d6e9c6;
border-radius: 4px;
color: #3c763d;
font-size: 1.1em;
text-align: center;
}
.calculator-info {
margin-top: 20px;
padding: 15px;
background-color: #fcf8e3;
border: 1px solid #faebcc;
border-radius: 4px;
color: #8a6d13;
font-size: 0.9em;
line-height: 1.4;
}