This calculator estimates the calories you burn during an exercise session based on your heart rate, duration, and personal metrics. Understanding your calorie expenditure can be a valuable tool for fitness tracking, weight management, and optimizing your workouts.
Male
Female
How it Works:
The calories burned during exercise are influenced by several factors, including your age, weight, height, gender, heart rate, and the duration of your activity. A higher heart rate generally indicates a more intense workout, leading to a greater calorie burn. This calculator uses a modified version of the general calorie expenditure formula, which takes into account your resting metabolic rate (estimated using the Mifflin-St Jeor equation for BMR) and then factors in the intensity of your exercise based on your heart rate.
Factors Considered:
Age: Metabolic rate can change with age.
Weight: Heavier individuals generally burn more calories.
Height: Affects body surface area and metabolic rate.
Gender: Men and women have different body compositions and metabolic rates.
Average Heart Rate: A key indicator of exercise intensity. Higher heart rates correlate with more calories burned.
Exercise Duration: The longer you exercise, the more calories you burn.
The Science Behind the Calculation:
The calculation begins by estimating your Basal Metabolic Rate (BMR) using the 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
This BMR represents the calories your body burns at rest. To estimate calories burned during exercise, we consider the intensity. A common approach is to use METs (Metabolic Equivalents), but a direct heart rate calculation provides a more personalized estimate. This calculator uses a simplified approach that relates heart rate to an approximate intensity factor. The total calories burned are then calculated as a function of your BMR, the intensity (approximated by heart rate relative to estimated max heart rate), and the duration.
Disclaimer:
This calculator provides an estimate. Actual calories burned can vary based on individual physiology, exercise efficiency, and the specific type of activity performed.
function calculateCaloriesBurned() {
var age = document.getElementById("age").value;
var weightKg = document.getElementById("weightKg").value;
var heightCm = document.getElementById("heightCm").value;
var gender = document.getElementById("gender").value;
var heartRate = document.getElementById("heartRate").value;
var durationMinutes = document.getElementById("durationMinutes").value;
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
if (!age || !weightKg || !heightCm || !heartRate || !durationMinutes) {
resultDiv.innerHTML = "Please fill in all required fields.";
return;
}
age = parseFloat(age);
weightKg = parseFloat(weightKg);
heightCm = parseFloat(heightCm);
heartRate = parseFloat(heartRate);
durationMinutes = parseFloat(durationMinutes);
if (isNaN(age) || isNaN(weightKg) || isNaN(heightCm) || isNaN(heartRate) || isNaN(durationMinutes) || age <= 0 || weightKg <= 0 || heightCm <= 0 || heartRate <= 0 || durationMinutes < 0) {
resultDiv.innerHTML = "Please enter valid positive numbers for all fields.";
return;
}
// Calculate BMR (Mifflin-St Jeor Equation)
var bmr = 0;
if (gender === "male") {
bmr = (10 * weightKg) + (6.25 * heightCm) – (5 * age) + 5;
} else { // female
bmr = (10 * weightKg) + (6.25 * heightCm) – (5 * age) – 161;
}
// Estimate calories burned based on heart rate and duration.
// This is a simplified model. More complex formulas exist.
// We'll use a factor that increases with heart rate.
// A common factor for moderate to high intensity might be around 0.05 to 0.15 kcal/minute/kg at various HR ranges.
// Let's create a simplified factor based on heart rate.
// We'll assume a resting heart rate around 60-70 bpm.
// Max heart rate is roughly 220 – age.
var maxHeartRate = 220 – age;
var heartRatePercentage = (heartRate / maxHeartRate) * 100;
var intensityFactor = 0;
if (heartRatePercentage = 50 && heartRatePercentage = 60 && heartRatePercentage = 70 && heartRatePercentage = 80 && heartRatePercentage < 90) {
intensityFactor = 0.11; // High Intensity
} else {
intensityFactor = 0.13; // Very High Intensity
}
// Approximate calories burned per minute
// This factor is a simplification and can vary greatly.
// A more precise calculation would involve METs or more detailed physiological models.
var caloriesPerMinute = (bmr / 24 / 60) * intensityFactor * 15; // Multiplier to approximate intensity
var totalCaloriesBurned = caloriesPerMinute * durationMinutes;
// Ensure result is not negative and has reasonable precision
totalCaloriesBurned = Math.max(0, totalCaloriesBurned).toFixed(2);
resultDiv.innerHTML = "Estimated Calories Burned: " + totalCaloriesBurned + " kcal";
}
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