Optimize your fitness training by identifying your ideal heart rate zones.
Estimated Maximum Heart Rate (MHR)
0
Beats Per Minute (BPM)
Zone
Intensity
Target Range (BPM)
Understanding Heart Rate Zones
Your heart rate is a direct window into your body's cardiovascular performance. By using a heart rate chart calculator, you can move away from guesswork and ensure every workout serves a specific purpose, whether it's burning fat, building endurance, or increasing your speed.
This calculator uses the Fox formula (220 – age) for basic calculations and incorporates the Karvonen Formula if you provide your resting heart rate. The Karvonen method is often considered more accurate for athletes because it accounts for individual fitness levels via Heart Rate Reserve (HRR).
Realistic Example:
If you are 40 years old with a resting heart rate of 60 BPM:
1. Your Max Heart Rate (MHR) is approximately 180 BPM (220 – 40).
2. To train in Zone 2 (Fat Burn), you would aim for roughly 120-132 BPM.
3. Training in Zone 4 (Anaerobic) would push you between 156-168 BPM.
The Five Heart Rate Zones Explained
Zone 1 (50-60%): Very Light. Best for warm-ups, cool-downs, and active recovery. It improves overall health but isn't strenuous.
Zone 2 (60-70%): Light. Often called the "Fat Burning Zone." This intensity builds basic endurance and allows the body to utilize fat as the primary fuel source.
Zone 3 (70-80%): Moderate. The aerobic zone. It improves cardiovascular capacity and strengthens the heart and lungs.
Zone 4 (80-90%): Hard. The anaerobic zone. Here, you build speed and power. You can only sustain this for a short duration.
Zone 5 (90-100%): Maximum. Reserved for interval training and elite performance. It develops maximal speed and muscular endurance.
Why Monitor Your Heart Rate?
Overtraining is a common hurdle for many fitness enthusiasts. By adhering to a heart rate chart, you can ensure you aren't pushing too hard on recovery days, while also ensuring your "hard" days are sufficiently intense to trigger physiological adaptations. Using a chest strap or optical wrist sensor in conjunction with these calculated zones provides the most actionable data for your fitness journey.
function calculateZones() {
var age = document.getElementById('hrAge').value;
var restingHR = document.getElementById('hrResting').value;
var resultsDiv = document.getElementById('hrResults');
var mhrValue = document.getElementById('mhrValue');
var tableBody = document.getElementById('zoneTableBody');
if (!age || age <= 0) {
alert("Please enter a valid age.");
return;
}
var ageNum = parseFloat(age);
var restNum = parseFloat(restingHR) || 0;
// Calculate Max Heart Rate (Fox Formula)
var mhr = 220 – ageNum;
mhrValue.innerText = mhr;
// Heart Rate Reserve (HRR) for Karvonen Formula
var hrr = mhr – restNum;
var zones = [
{ name: "Zone 1 (Warm up)", intensity: "50-60%", min: 0.50, max: 0.60, class: "hr-zone-1" },
{ name: "Zone 2 (Fat Burn)", intensity: "60-70%", min: 0.60, max: 0.70, class: "hr-zone-2" },
{ name: "Zone 3 (Aerobic)", intensity: "70-80%", min: 0.70, max: 0.80, class: "hr-zone-3" },
{ name: "Zone 4 (Anaerobic)", intensity: "80-90%", min: 0.80, max: 0.90, class: "hr-zone-4" },
{ name: "Zone 5 (Red Line)", intensity: "90-100%", min: 0.90, max: 1.00, class: "hr-zone-5" }
];
var html = "";
for (var i = 0; i 0) {
// Use Karvonen Formula: ((MHR – RHR) * %Intensity) + RHR
low = Math.round((hrr * zones[i].min) + restNum);
high = Math.round((hrr * zones[i].max) + restNum);
} else {
// Use standard MHR percentage
low = Math.round(mhr * zones[i].min);
high = Math.round(mhr * zones[i].max);
}
html += "