Max Heart Rate Calculator
.mhr-calculator-wrapper {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 20px auto;
padding: 20px;
border: 1px solid #e0e0e0;
border-radius: 8px;
background-color: #f9f9f9;
color: #333;
}
.mhr-calc-container {
display: flex;
flex-wrap: wrap;
gap: 20px;
}
.mhr-inputs {
flex: 1;
min-width: 300px;
padding: 20px;
background: #ffffff;
border-radius: 8px;
box-shadow: 0 2px 5px rgba(0,0,0,0.05);
}
.mhr-results {
flex: 1;
min-width: 300px;
padding: 20px;
background: #ffffff;
border-radius: 8px;
box-shadow: 0 2px 5px rgba(0,0,0,0.05);
display: none; /* Hidden by default */
}
.form-group {
margin-bottom: 15px;
}
.form-group label {
display: block;
margin-bottom: 5px;
font-weight: 600;
color: #2c3e50;
}
.form-group input, .form-group select {
width: 100%;
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.calculate-btn {
width: 100%;
padding: 12px;
background-color: #e74c3c;
color: white;
border: none;
border-radius: 4px;
font-size: 16px;
font-weight: bold;
cursor: pointer;
transition: background 0.3s;
}
.calculate-btn:hover {
background-color: #c0392b;
}
.result-header {
text-align: center;
margin-bottom: 20px;
border-bottom: 2px solid #f0f0f0;
padding-bottom: 10px;
}
.big-number {
font-size: 3em;
font-weight: 800;
color: #e74c3c;
line-height: 1;
}
.bpm-label {
font-size: 1.2em;
color: #7f8c8d;
}
.zones-table {
width: 100%;
border-collapse: collapse;
margin-top: 20px;
font-size: 14px;
}
.zones-table th, .zones-table td {
padding: 10px;
text-align: left;
border-bottom: 1px solid #eee;
}
.zones-table th {
background-color: #f8f9fa;
font-weight: 600;
}
.zone-color {
width: 15px;
height: 15px;
display: inline-block;
border-radius: 50%;
margin-right: 8px;
vertical-align: middle;
}
.mhr-content {
margin-top: 40px;
line-height: 1.6;
}
.mhr-content h2 {
color: #2c3e50;
border-bottom: 2px solid #e74c3c;
padding-bottom: 10px;
margin-top: 30px;
}
.mhr-content h3 {
color: #34495e;
margin-top: 25px;
}
.mhr-content ul {
padding-left: 20px;
}
.mhr-content li {
margin-bottom: 10px;
}
@media (max-width: 600px) {
.mhr-calc-container {
flex-direction: column;
}
}
Target Training Zones
| Zone |
Intensity |
Range (BPM) |
Understanding Your Maximum Heart Rate
Your Maximum Heart Rate (MHR) is the highest number of beats per minute (BPM) your heart can achieve during maximum physical exertion. It is a critical metric used to define training zones, ensuring that your workouts are safe, effective, and aligned with your fitness goals.
Knowing your MHR allows you to train smarter, not just harder. Whether you are aiming for fat loss, cardiovascular endurance, or peak athletic performance, staying within specific heart rate percentages relative to your max is the key to progress.
Calculation Formulas Explained
While the "220 minus age" rule is the most famous, researchers have developed several formulas to estimate MHR more accurately for different populations:
- Fox Formula (220 – Age): The traditional standard. It is simple to use but can overestimate MHR in young people and underestimate it in older adults.
- Tanaka Formula (208 – 0.7 × Age): Often considered more accurate for healthy adults, particularly those over the age of 40.
- Gellish Formula (207 – 0.7 × Age): A non-linear equation that provides a slightly more precise regression line for age-related heart rate decline.
- Gulati Formula (206 – 0.88 × Age): Research suggests women often have a different heart rate decline than men; this formula is specifically adjusted for female physiology.
Heart Rate Training Zones
Once you know your MHR, you can target specific energy systems by training in these zones:
- Zone 1 (50-60%): Very Light. Improves overall health and helps with recovery. Great for warming up.
- Zone 2 (60-70%): Light. The "Fat Burning" zone. Builds basic endurance and aerobic capacity.
- Zone 3 (70-80%): Moderate. Improves aerobic fitness. This is where you begin to sweat and breathing becomes rhythmic.
- Zone 4 (80-90%): Hard. Increases maximum performance capacity. Sustainable for shorter periods.
- Zone 5 (90-100%): Maximum. Develops maximum speed and power. Can only be sustained for very short bursts.
Factors Influencing Maximum Heart Rate
It is important to remember that these calculators provide estimates. Your actual max heart rate can be influenced by:
- Genetics: Just like height, MHR is largely determined by hereditary factors.
- Altitude: High altitudes can lower your attainable maximum heart rate.
- Age: MHR naturally declines as we get older, roughly by one beat per year.
- Medication: Beta-blockers and other medications can significantly lower your heart rate.
function calculateMaxHeartRate() {
// 1. Get inputs
var ageInput = document.getElementById('mhrAge');
var formulaSelect = document.getElementById('mhrFormula');
var resultContainer = document.getElementById('mhrResults');
var resultValueDisplay = document.getElementById('resultValue');
var zonesBody = document.getElementById('zonesBody');
var age = parseFloat(ageInput.value);
var formula = formulaSelect.value;
// 2. Validate Input
if (isNaN(age) || age 120) {
alert("Please enter a valid age between 1 and 120.");
return;
}
// 3. Calculate MHR based on selected formula
var mhr = 0;
if (formula === 'fox') {
mhr = 220 – age;
} else if (formula === 'tanaka') {
mhr = 208 – (0.7 * age);
} else if (formula === 'gellish') {
mhr = 207 – (0.7 * age);
} else if (formula === 'gulati') {
mhr = 206 – (0.88 * age);
}
// Round to nearest whole number
mhr = Math.round(mhr);
// 4. Calculate Zones
// Zone 1: 50-60%
var z1_low = Math.round(mhr * 0.50);
var z1_high = Math.round(mhr * 0.60);
// Zone 2: 60-70%
var z2_low = Math.round(mhr * 0.60);
var z2_high = Math.round(mhr * 0.70);
// Zone 3: 70-80%
var z3_low = Math.round(mhr * 0.70);
var z3_high = Math.round(mhr * 0.80);
// Zone 4: 80-90%
var z4_low = Math.round(mhr * 0.80);
var z4_high = Math.round(mhr * 0.90);
// Zone 5: 90-100%
var z5_low = Math.round(mhr * 0.90);
var z5_high = mhr;
// 5. Update UI
resultValueDisplay.innerHTML = mhr;
// Clear previous table rows
zonesBody.innerHTML = ";
// Helper function to create row
function createRow(zoneName, intensity, range, color) {
return '
' +
'| ' + zoneName + ' | ' +
'' + intensity + ' | ' +
'' + range + ' bpm | ' +
'
';
}
var rows = ";
rows += createRow('Zone 1', 'Very Light / Warm Up', z1_low + ' – ' + z1_high, '#a8e6cf');
rows += createRow('Zone 2', 'Light / Fat Burn', z2_low + ' – ' + z2_high, '#dcedc1');
rows += createRow('Zone 3', 'Moderate / Aerobic', z3_low + ' – ' + z3_high, '#ffd3b6');
rows += createRow('Zone 4', 'Hard / Anaerobic', z4_low + ' – ' + z4_high, '#ffaaa5');
rows += createRow('Zone 5', 'Maximum / VO2 Max', z5_low + ' – ' + z5_high, '#ff8b94');
zonesBody.innerHTML = rows;
// Show result container
resultContainer.style.display = 'block';
}