function calculateKcalBurned() {
var activityMet = parseFloat(document.getElementById('activity').value);
var weight = parseFloat(document.getElementById('weight').value);
var unit = document.getElementById('unit').value;
var duration = parseFloat(document.getElementById('duration').value);
var resultBox = document.getElementById('result-box');
var resultValue = document.getElementById('result-value');
if (isNaN(weight) || isNaN(duration) || weight <= 0 || duration <= 0) {
alert('Please enter valid positive numbers for weight and duration.');
return;
}
var weightInKg = weight;
if (unit === 'lbs') {
weightInKg = weight * 0.453592;
}
// Formula: Kcal = MET * Weight(kg) * (Duration(mins) / 60)
var totalKcal = activityMet * weightInKg * (duration / 60);
resultValue.innerHTML = Math.round(totalKcal).toLocaleString();
resultBox.style.display = 'block';
}
How Does the Kcal Burned Calculator Work?
To determine the energy expenditure of any physical activity, we use the **MET** (Metabolic Equivalent of Task) system. MET is a physiological measure expressing the energy cost of specific physical activities. One MET is defined as the energy you burn while sitting at rest.
The MET Calculation Formula
The scientific formula used by this calculator is:
Calories Burned = MET × Weight (kg) × Duration (hours)
Why Use This Calculator?
Whether your goal is weight loss, muscle maintenance, or improving athletic performance, tracking your "calories out" is essential. By entering your specific weight and the exact duration of your exercise, you get a personalized estimate that is much more accurate than a general gym chart.
Personalized Data: Takes into account your body mass for more accurate results.
Broad Activity Range: Covers everything from intense sprinting to light household cleaning.
Goal Tracking: Helps you manage your caloric deficit or surplus for fitness goals.
Realistic Examples
Activity
Weight
Duration
Kcal Burned
Brisk Walking
70 kg
60 min
~350 kcal
Running (8 mph)
180 lbs
30 min
~469 kcal
Yoga
65 kg
45 min
~122 kcal
Note: Caloric burn is an estimate. Real-world factors like metabolic rate, age, muscle mass, and environmental conditions (temperature/altitude) also play a role in actual energy expenditure.