Calculate your MHR and training zones based on age, gender, weight, and height.
Male
Female
Max Heart Rate (Fox)
0
bpm
Max Heart Rate (Tanaka)
0
bpm
Your BMI
0
kg/m²
Target Heart Rate Training Zones
Based on your calculated Maximum Heart Rate (Fox Formula):
Zone
Intensity
Heart Rate Range
Benefit
function calculateHeartRate() {
// Get Input Values
var age = parseFloat(document.getElementById('mhr_age').value);
var gender = document.getElementById('mhr_gender').value;
var height = parseFloat(document.getElementById('mhr_height').value);
var weight = parseFloat(document.getElementById('mhr_weight').value);
var restingHR = parseFloat(document.getElementById('mhr_resting').value);
// Validation
if (isNaN(age) || age 0) {
var heightInMeters = height / 100;
bmi = (weight / (heightInMeters * heightInMeters)).toFixed(1);
if (bmi < 18.5) bmiText = "Underweight";
else if (bmi < 25) bmiText = "Normal Weight";
else if (bmi 0 && restingHR < mhrFox;
function calcZone(percent) {
if (useKarvonen) {
return Math.round(((mhrFox – restingHR) * percent) + restingHR);
}
return Math.round(mhrFox * percent);
}
var z1_min = calcZone(0.50); var z1_max = calcZone(0.60);
var z2_min = calcZone(0.60); var z2_max = calcZone(0.70);
var z3_min = calcZone(0.70); var z3_max = calcZone(0.80);
var z4_min = calcZone(0.80); var z4_max = calcZone(0.90);
var z5_min = calcZone(0.90); var z5_max = mhrFox;
// Update DOM
document.getElementById('res_mhr_fox').innerText = mhrFox;
var secLabelElem = document.querySelectorAll('.result-card h4')[1];
secLabelElem.innerText = labelSecondary;
document.getElementById('res_mhr_tanaka').innerText = mhrSecondary;
document.getElementById('res_bmi').innerText = bmi;
var bmiMsg = "Based on your inputs: Your calculated BMI is " + bmi + " (" + bmiText + "). ";
if (useKarvonen) {
bmiMsg += "Training zones calculated using the Karvonen Formula (Heart Rate Reserve) based on your resting heart rate.";
} else {
bmiMsg += "Training zones calculated using the standard percentage of Maximum Heart Rate.";
}
document.getElementById('bmi_message').innerHTML = bmiMsg;
// Build Table
var tableHTML = `
Your Maximum Heart Rate (MHR) is the highest number of beats per minute (bpm) your heart can pump under maximum stress. Knowing this number is crucial for athletes and fitness enthusiasts to establish effective training zones.
Why Ask for Age, Weight, and Height?
While the most common formula for Maximum Heart Rate relies primarily on Age, a comprehensive fitness assessment requires looking at the whole picture:
Age: This is the primary determinant of MHR. Generally, your maximum heart rate declines as you get older.
Weight & Height: These inputs allow us to calculate your Body Mass Index (BMI). While being heavier or taller doesn't directly change the electrical limit of your heart (MHR), it significantly impacts the effort required to reach specific heart rate zones. A higher BMI often correlates with a higher workload on the heart during exercise.
The Formulas Used
This calculator utilizes industry-standard formulas to estimate your limits:
The Fox Formula:220 - Age. This is the most widely used and simple calculation for estimating MHR.
The Tanaka Formula:208 - (0.7 × Age). Often considered more accurate for adults over the age of 40.
The Gulati Formula (for Women):206 - (0.88 × Age). Research suggests this formula is more accurate for predicting peak heart rate in women.
Heart Rate Training Zones Explained
Once your MHR is calculated, we can determine your training zones. If you provide your Resting Heart Rate, the calculator upgrades to the Karvonen Method, which accounts for your "Heart Rate Reserve" (the difference between your max and resting rates). This provides a much more personalized target for your workouts.
Fat Burn Zone (60-70%): Ideal for weight loss and building endurance foundation.
Cardio Zone (70-80%): The "sweet spot" for improving cardiovascular health and aerobic capacity.
Peak Zone (90-100%): Only sustainable for short bursts; used for high-intensity interval training (HIIT).
Medical Disclaimer: This calculator provides estimates based on population averages. Actual maximum heart rate can vary significantly due to genetics, medication, and fitness levels. Always consult a physician before starting a new exercise regimen, especially if you have a history of heart conditions.