Estimated Max Heart Rate0 BPM
Based on Standard Formula
Training Zones
Zone
Intensity
Range (BPM)
Benefit
function calculateHeartRate() {
// 1. Get Inputs
var ageInput = document.getElementById('mhrAge');
var genderInput = document.getElementById('mhrGender');
var restingInput = document.getElementById('mhrResting');
var resultsDiv = document.getElementById('mhrResults');
var displayMHR = document.getElementById('displayMHR');
var formulaLabel = document.getElementById('formulaUsed');
var zonesBody = document.getElementById('zonesBody');
var methodLabel = document.getElementById('methodLabel');
var age = parseFloat(ageInput.value);
var gender = genderInput.value;
var restingHR = parseFloat(restingInput.value);
// 2. Validation
if (isNaN(age) || age 120) {
alert("Please enter a valid age between 1 and 120.");
return;
}
// 3. Calculate Max Heart Rate (MHR)
// Using Tanaka formula for general accuracy, or Gulati for women if specified,
// but often the standard Fox (220-age) is expected.
// Let's implement a hybrid logic for best accuracy:
// Tanaka (208 – 0.7 * age) is generally accepted as more accurate than Fox.
// Gulati (206 – 0.88 * age) is specific for women.
var mhr = 0;
var formulaName = "";
if (gender === 'female') {
// Gulati Formula for women
mhr = 206 – (0.88 * age);
formulaName = "Gulati Formula (Specific for Women)";
} else {
// Tanaka Formula for general/male
mhr = 208 – (0.7 * age);
formulaName = "Tanaka Formula (208 – 0.7 × Age)";
}
mhr = Math.round(mhr);
// 4. Calculate Zones
// If Resting HR is provided, use Karvonen Formula: Target = ((Max – Resting) * %) + Resting
// If not, use standard Percentage of Max HR: Target = Max * %
var useKarvonen = !isNaN(restingHR) && restingHR > 30 && restingHR < 150;
var zones = [
{ name: "Zone 1", label: "Very Light", minPct: 0.50, maxPct: 0.60, desc: "Warm up, Recovery", class: "zone-1" },
{ name: "Zone 2", label: "Light", minPct: 0.60, maxPct: 0.70, desc: "Fat Burning, Endurance", class: "zone-2" },
{ name: "Zone 3", label: "Moderate", minPct: 0.70, maxPct: 0.80, desc: "Aerobic Fitness", class: "zone-3" },
{ name: "Zone 4", label: "Hard", minPct: 0.80, maxPct: 0.90, desc: "Anaerobic Threshold", class: "zone-4" },
{ name: "Zone 5", label: "Maximum", minPct: 0.90, maxPct: 1.00, desc: "Peak Performance", class: "zone-5" }
];
var tableHTML = "";
for (var i = 0; i < zones.length; i++) {
var z = zones[i];
var minBPM, maxBPM;
if (useKarvonen) {
// Karvonen Calculation
// THR = ((MHR – RHR) * %Intensity) + RHR
var reserve = mhr – restingHR;
minBPM = Math.round((reserve * z.minPct) + restingHR);
maxBPM = Math.round((reserve * z.maxPct) + restingHR);
} else {
// Standard Calculation
minBPM = Math.round(mhr * z.minPct);
maxBPM = Math.round(mhr * z.maxPct);
}
tableHTML += "
Understanding how to calculate your max heart rate (MHR) is the foundation of effective cardiovascular training. Your maximum heart rate represents the highest number of beats per minute (BPM) your heart can achieve during maximum physical exertion. By identifying this number, you can define specific heart rate zones to tailor your workouts for fat loss, endurance, or peak athletic performance.
Common Formulas for Calculation
While a clinical stress test is the most accurate method, several mathematical formulas provide reliable estimates based on age and gender. This calculator uses the most scientifically robust options available:
Fox Formula (Standard):220 – Age. This is the oldest and most common method, though it can oversimplify results for very fit or older individuals.
Tanaka Formula:208 – (0.7 × Age). Often considered more accurate for adults over age 40.
Gulati Formula (For Women):206 – (0.88 × Age). Research suggests this formula predicts max heart rate more accurately for women than the standard male-centric equations.
Why Resting Heart Rate Matters
If you enter your Resting Heart Rate in the calculator above, the results switch to the Karvonen Method. This method calculates your "Heart Rate Reserve" (Max HR minus Resting HR) to determine training zones. This is generally preferred for athletes because it accounts for your current fitness level. A lower resting heart rate usually indicates better cardiovascular health, changing the boundaries of your training zones.
Understanding Heart Rate Zones
Once you know your MHR, you can target specific zones to achieve different fitness goals:
Zone 1 (50-60%): Very light activity, used for warm-ups and active recovery.
Zone 2 (60-70%): The "Fat Burning" zone. Your body becomes efficient at metabolizing fat for fuel. Ideal for building endurance.
Zone 3 (70-80%): Aerobic zone. Improves blood circulation and lung capacity.
Zone 4 (80-90%): Anaerobic zone. You start producing lactic acid. This improves high-speed endurance.
Zone 5 (90-100%): Maximum effort. Sustainable only for very short bursts. Used for interval training.
Safety Considerations
Please note that these calculations are estimates. Genetics, medication, and altitude can affect your actual maximum heart rate. If you are new to exercise or have a heart condition, consult a physician before attempting to reach your maximum heart rate or engaging in Zone 4-5 training.