Calculate your Body Mass Index (BMI) to understand your weight category and guide your weight loss efforts.
Your Results
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Understanding Your BMI and Weight Loss
Body Mass Index (BMI) is a simple and widely used tool to estimate whether an individual is at a healthy weight for their height. It's a crucial first step in understanding your current health status and can be a significant motivator and guide for weight loss journeys. While BMI doesn't directly measure body fat, it correlates well with it for most people.
How BMI is Calculated
The formula for BMI is:
BMI = Weight (kg) / (Height (m))^2
In this calculator, we use your input in kilograms (kg) for weight and centimeters (cm) for height. The calculator automatically converts your height to meters (by dividing by 100) before applying the formula.
For example, if you weigh 70 kg and your height is 175 cm:
Convert height to meters: 175 cm / 100 = 1.75 m
Calculate BMI: 70 kg / (1.75 m * 1.75 m) = 70 / 3.0625 = 22.86
Your BMI is approximately 22.86.
BMI Categories and What They Mean for Weight Loss
The calculated BMI is then compared against standard weight categories:
Underweight: BMI below 18.5. You might need to focus on healthy weight gain strategies.
Normal weight: BMI between 18.5 and 24.9. This range is generally considered healthy. For weight loss, focus on maintaining a healthy lifestyle and sustainable habits.
Overweight: BMI between 25.0 and 29.9. This category suggests you may benefit from weight loss to reduce health risks. Focus on a balanced diet and regular exercise.
Obese: BMI of 30.0 or higher. This indicates a higher risk of various health conditions, and significant weight loss is often recommended. Consult with a healthcare professional for a tailored plan.
Using BMI for Your Weight Loss Journey
Your BMI is a starting point, not a definitive diagnosis. It can help you:
Set Realistic Goals: If you are overweight or obese, your BMI can help you understand how much weight you might need to lose to reach a healthier category.
Track Progress: Regularly recalculating your BMI as you lose weight can provide tangible evidence of your progress, boosting motivation.
Identify Health Risks: A BMI in the overweight or obese range is associated with increased risks of conditions like heart disease, type 2 diabetes, and high blood pressure.
Important Note: BMI is a general indicator. Factors like muscle mass, bone density, and body composition can influence its accuracy. For personalized advice on weight management and health, always consult with a doctor or a registered dietitian.
function calculateBMI() {
var weight = document.getElementById("weight").value;
var height = document.getElementById("height").value;
var resultDiv = document.getElementById("result");
var bmiValueDiv = document.getElementById("bmiValue");
var bmiCategoryDiv = document.getElementById("bmiCategory");
var bmiDescriptionDiv = document.getElementById("bmiDescription");
// Clear previous results and styling
bmiValueDiv.textContent = "–";
bmiCategoryDiv.textContent = "–";
bmiDescriptionDiv.textContent = "";
bmiCategoryDiv.className = "bmi-category"; // Reset classes
if (weight === "" || height === "" || isNaN(weight) || isNaN(height) || weight <= 0 || height <= 0) {
resultDiv.style.borderColor = "#dc3545";
bmiCategoryDiv.textContent = "Invalid Input";
bmiCategoryDiv.style.color = "#dc3545";
return;
}
var weightKg = parseFloat(weight);
var heightCm = parseFloat(height);
// Convert height from cm to meters
var heightM = heightCm / 100;
// Calculate BMI
var bmi = weightKg / (heightM * heightM);
var roundedBMI = bmi.toFixed(2);
var category = "";
var description = "";
var categoryClass = "";
if (bmi = 18.5 && bmi = 25.0 && bmi = 30.0
category = "Obese";
description = "Your BMI is in the obese range. This carries a higher risk of health problems. A structured weight loss plan with professional guidance is recommended.";
categoryClass = "obese";
}
bmiValueDiv.textContent = roundedBMI;
bmiCategoryDiv.textContent = category;
bmiCategoryDiv.className = "bmi-category " + categoryClass; // Add specific class for color
bmiDescriptionDiv.textContent = description;
resultDiv.style.borderColor = "#004a99"; // Reset border color
}