Fox Formula (Standard: 220 – Age)
Tanaka Formula (Precise: 208 – 0.7 × Age)
Estimated Max Heart Rate:— BPM
Target Training Zones
Intensity
Zone
Range (BPM)
Moderate
50% – 70%
—
Vigorous
70% – 85%
—
Peak/Sprint
85% – 100%
—
Understanding Maximum Heart Rate by Age
Your Maximum Heart Rate (MHR) is the highest number of beats per minute (BPM) your heart can safely reach during maximum exertion. Knowing this number is critical for athletes, fitness enthusiasts, and those undergoing cardiac rehabilitation to ensure they are training at an intensity that is both safe and effective for their goals.
How is Maximum Heart Rate Calculated?
While the most accurate way to find your MHR is through a clinical stress test supervised by a physician, mathematical formulas provide a reliable estimate for the general population. Our calculator utilizes the two most common methods:
The Fox Formula: Developed in the 1970s, this is the classic 220 - age equation. It is simple and widely used by fitness apps and gym equipment.
The Tanaka Formula: Published in 2001, this formula 208 - (0.7 × age) is often considered more accurate for adults over 40, as it accounts for the physiological changes that occur with aging more effectively than the Fox method.
Heart Rate Zones Explained
Once you know your maximum heart rate, you can divide your training into specific zones:
Moderate Intensity (50% to 70% of MHR): This is the "fat-burning" zone. It is ideal for warm-ups, cool-downs, and building base aerobic endurance. You should be able to carry on a conversation in this zone.
Vigorous Intensity (70% to 85% of MHR): This is the aerobic zone. It improves cardiovascular fitness and increases respiratory capacity. Conversation becomes difficult here.
Anaerobic/Peak Intensity (85% to 100% of MHR): This is for short bursts of high-intensity interval training (HIIT). It improves speed and power but can only be sustained for very short durations.
Example Calculation
If you are a 40-year-old individual using the Fox Formula:
Calculation: 220 – 40 = 180 BPM.
Moderate Zone (50-70%): 90 to 126 BPM.
Vigorous Zone (70-85%): 126 to 153 BPM.
Important Safety Considerations
Please note that these formulas provide estimates. Individual heart rates can vary significantly based on genetics, fitness level, medications (like beta-blockers), and environmental factors like heat or altitude. Always consult with a healthcare professional before starting a new, high-intensity exercise program, especially if you have a history of heart conditions or are currently inactive.
function calculateMHR() {
var ageInput = document.getElementById('userAge');
var formula = document.getElementById('hrFormula').value;
var age = parseFloat(ageInput.value);
var resultsDiv = document.getElementById('hrResults');
var maxResultText = document.getElementById('maxResult');
var zoneModText = document.getElementById('zoneModerate');
var zoneVigText = document.getElementById('zoneVigorous');
var zonePeakText = document.getElementById('zonePeak');
if (isNaN(age) || age 120) {
alert("Please enter a valid age between 1 and 120.");
return;
}
var mhr = 0;
if (formula === 'fox') {
mhr = 220 – age;
} else if (formula === 'tanaka') {
mhr = 208 – (0.7 * age);
}
mhr = Math.round(mhr);
// Calculate Zones
var modLow = Math.round(mhr * 0.50);
var modHigh = Math.round(mhr * 0.70);
var vigLow = Math.round(mhr * 0.70);
var vigHigh = Math.round(mhr * 0.85);
var peakLow = Math.round(mhr * 0.85);
// Display Results
maxResultText.innerHTML = mhr + " BPM";
zoneModText.innerHTML = modLow + " – " + modHigh + " BPM";
zoneVigText.innerHTML = vigLow + " – " + vigHigh + " BPM";
zonePeakText.innerHTML = peakLow + " – " + mhr + " BPM";
resultsDiv.style.display = 'block';
}