Fox Formula (Standard: 220 – Age)
Tanaka Formula (More accurate: 208 – 0.7 × Age)
Gulati Formula (Women specific: 206 – 0.88 × Age)
Predicted Maximum Heart Rate
0Beats Per Minute (BPM)
Target Heart Rate Zones
Zone
Intensity
Heart Rate Range
*These zones are estimates based on your MHR. Consult a physician before starting new high-intensity training.
How to Calculate Age Predicted Maximum Heart Rate
Understanding your Maximum Heart Rate (MHR) is a fundamental aspect of cardiovascular training. Whether you are an elite athlete or someone just starting their fitness journey, knowing your physiological limits helps in structuring effective workout plans. The age-predicted maximum heart rate is a calculation used to estimate the highest number of beats per minute your heart can safely achieve under maximum stress.
Why Calculate Your Max Heart Rate?
Your MHR serves as the ceiling for your cardiovascular capacity. Once this number is determined, it becomes the anchor point for defining your specific heart rate training zones. Training in specific zones yields different physiological adaptations:
Fat Burning: Lower intensity zones rely more on fat oxidation for fuel.
Aerobic Capacity: Moderate zones improve your heart's efficiency and lung capacity.
Anaerobic Threshold: High-intensity zones improve your ability to sustain power output and clear lactate.
The Formulas Explained
While the most common rule of thumb is simply subtracting your age from 220, exercise physiology has evolved to provide more nuanced formulas.
1. The Fox Formula (220 – Age)
This is the most widely recognized formula due to its simplicity. Proposed in 1971, it provides a rough estimate suitable for the general population. However, it often underestimates MHR for older adults and overestimates it for younger individuals. Despite its criticism regarding precision, it remains the standard for basic fitness prescriptions.
2. The Tanaka Formula (208 – 0.7 × Age)
Published in 2001, the Tanaka equation is considered more accurate across a wider range of ages. It accounts for the non-linear decline of heart rate as we age. For healthy adults, this formula typically provides a result that is closer to laboratory-measured maximums than the Fox formula.
3. The Gulati Formula (206 – 0.88 × Age)
Research specifically focused on women has shown that the standard male-centric formulas often overestimate MHR in females. The Gulati formula is derived from a study of over 5,000 asymptomatic women and is generally recommended for female athletes to prevent training at intensities that are effectively higher than intended.
Understanding Heart Rate Zones
Once you calculate your MHR, you can derive your training zones. These are calculated as percentages of your max:
Zone 1 (50-60%): Very Light. Good for warm-ups and recovery.
Zone 2 (60-70%): Light. The "fat burning" zone where you can hold a conversation.
Zone 3 (70-80%): Moderate. Improves aerobic fitness and blood circulation.
Zone 4 (80-90%): Hard. Increases maximum performance capacity.
Zone 5 (90-100%): Maximum. Develops maximum speed and power (short bursts only).
Limitations of Prediction
It is important to remember that these calculations are statistical averages. Your actual maximum heart rate can be influenced by genetics, medication (such as beta-blockers), altitude, and fitness level. The only way to determine your true MHR is through a graded exercise stress test performed under medical supervision. For most recreational athletes, however, age-predicted formulas provide a safe and effective baseline for training.
function calculateMHR() {
// 1. Get Inputs
var ageInput = document.getElementById('currentAge');
var genderInput = document.getElementById('genderSelect');
var formulaInput = document.getElementById('formulaType');
var errorDiv = document.getElementById('ageError');
var resultArea = document.getElementById('result-area');
var age = parseFloat(ageInput.value);
var gender = genderInput.value;
var formula = formulaInput.value;
// 2. Validation
if (isNaN(age) || age 120) {
errorDiv.style.display = 'block';
resultArea.style.display = 'none';
return;
} else {
errorDiv.style.display = 'none';
}
// 3. Calculation Logic
var maxHeartRate = 0;
if (formula === 'fox') {
// Standard Formula: 220 – Age
maxHeartRate = 220 – age;
} else if (formula === 'tanaka') {
// Tanaka Formula: 208 – (0.7 * Age)
maxHeartRate = 208 – (0.7 * age);
} else if (formula === 'gulati') {
// Gulati Formula: 206 – (0.88 * Age)
// Note: If a male selects Gulati, we technically calculate it,
// but usually we might warn them. For this tool, we just run the math.
maxHeartRate = 206 – (0.88 * age);
}
// Round to nearest whole number
maxHeartRate = Math.round(maxHeartRate);
// 4. Calculate Zones
// Zone 1: 50-60%
var z1_low = Math.round(maxHeartRate * 0.50);
var z1_high = Math.round(maxHeartRate * 0.60);
// Zone 2: 60-70%
var z2_low = Math.round(maxHeartRate * 0.60);
var z2_high = Math.round(maxHeartRate * 0.70);
// Zone 3: 70-80%
var z3_low = Math.round(maxHeartRate * 0.70);
var z3_high = Math.round(maxHeartRate * 0.80);
// Zone 4: 80-90%
var z4_low = Math.round(maxHeartRate * 0.80);
var z4_high = Math.round(maxHeartRate * 0.90);
// Zone 5: 90-100%
var z5_low = Math.round(maxHeartRate * 0.90);
var z5_high = maxHeartRate;
// 5. Update UI
document.getElementById('bpmDisplay').innerText = maxHeartRate;
var tbody = document.getElementById('zonesBody');
tbody.innerHTML = "; // Clear previous
// Helper to create row
function createRow(cls, zoneName, intensity, range) {
return '