Calculate your Max Heart Rate (MHR) and training zones based on your Resting Heart Rate (RHR).
Please enter valid numeric values for Age and Resting Heart Rate.
Best measured in the morning before getting out of bed.
0 bpm
Est. Max Heart Rate
0 bpm
Heart Rate Reserve
Your Training Zones
Zone
Intensity
Target Range (BPM)
Benefit
Understanding the Max Heart Rate Resting Calculator
This calculator utilizes the Karvonen Formula, widely regarded by exercise physiologists as a more accurate method for determining training intensity than standard max heart rate calculations alone. Unlike simple formulas that only consider your age, this method incorporates your Resting Heart Rate (RHR), adjusting the zones to your specific fitness level.
How the Calculation Works
The logic follows three main steps to determine your optimal training zones:
Maximum Heart Rate (MHR): We estimate your absolute maximum capacity using the standard formula: 220 – Age = MHR.
Heart Rate Reserve (HRR): This represents the difference between your maximum capacity and your baseline resting rate. MHR – Resting Heart Rate = HRR.
Target Heart Rate (THR): We calculate specific zones by taking a percentage of your reserve and adding your resting rate back in. (HRR × Intensity %) + Resting Heart Rate = THR.
Why Resting Heart Rate Matters
Your Resting Heart Rate is a strong indicator of cardiovascular health. A lower RHR generally indicates a more efficient heart and higher aerobic fitness. By including RHR in the calculation, a fit individual with a low resting rate (e.g., 50 bpm) will get different training zones than an untrained individual with a high resting rate (e.g., 80 bpm), even if they are the same age.
Heart Rate Training Zones Explained
Zone 1 (Very Light): Used for warm-ups and active recovery. This helps blood flow and reduces soreness.
Zone 2 (Light): The "Fat Burning" zone. You should be able to hold a conversation easily. This builds basic endurance.
Zone 3 (Moderate): Improves aerobic fitness and blood circulation in skeletal muscles. Breathing becomes heavier.
Zone 4 (Hard): Increases maximum performance capacity. This is the anaerobic threshold zone where lactic acid begins to build up.
Zone 5 (Maximum): For athletic performance and speed. Sustainable for only very short periods.
How to Measure Your Resting Heart Rate
To get the most accurate result from this calculator, measure your pulse immediately after waking up in the morning, before getting out of bed or drinking caffeine. Count your heartbeats for 60 seconds, or count for 15 seconds and multiply by 4.
function calculateHeartRateZones() {
// 1. Get input values
var ageInput = document.getElementById('userAge');
var rhrInput = document.getElementById('restingHeartRate');
var resultDiv = document.getElementById('hrResults');
var errorDiv = document.getElementById('hrError');
var displayMax = document.getElementById('displayMaxHR');
var displayRes = document.getElementById('displayReserve');
var tableBody = document.getElementById('zonesTableBody');
// 2. Parse values
var age = parseFloat(ageInput.value);
var rhr = parseFloat(rhrInput.value);
// 3. Validate Inputs
if (isNaN(age) || isNaN(rhr) || age < 1 || rhr = estMHR) {
errorDiv.innerHTML = "Your Resting Heart Rate cannot be higher than or equal to your estimated Max Heart Rate (" + estMHR + "). Check your inputs.";
errorDiv.style.display = 'block';
resultDiv.style.display = 'none';
return;
}
// Hide error if valid
errorDiv.style.display = 'none';
// 4. Perform Calculation (Karvonen Method)
// Formula: Target = ((Max – Resting) * Intensity) + Resting
var mhr = 220 – age;
var hrr = mhr – rhr; // Heart Rate Reserve
// 5. Update Summary Cards
displayMax.innerHTML = Math.round(mhr) + " bpm";
displayRes.innerHTML = Math.round(hrr) + " bpm";
// 6. Calculate Zones
// Zone Definition:
// Z1: 50-60%
// Z2: 60-70%
// Z3: 70-80%
// Z4: 80-90%
// Z5: 90-100%
var zones = [
{ id: 1, name: "Very Light / Recovery", minPct: 0.50, maxPct: 0.60, benefit: "Warm up, recovery" },
{ id: 2, name: "Light / Fat Burn", minPct: 0.60, maxPct: 0.70, benefit: "Endurance, fat metabolism" },
{ id: 3, name: "Moderate / Aerobic", minPct: 0.70, maxPct: 0.80, benefit: "Aerobic fitness" },
{ id: 4, name: "Hard / Anaerobic", minPct: 0.80, maxPct: 0.90, benefit: "High speed endurance" },
{ id: 5, name: "Maximum / VO2 Max", minPct: 0.90, maxPct: 1.00, benefit: "Max effort, sprinting" }
];
var htmlRows = "";
for (var i = 0; i < zones.length; i++) {
var z = zones[i];
// Calculate low end of zone
var lowBPM = Math.round((hrr * z.minPct) + rhr);
// Calculate high end of zone
var highBPM = Math.round((hrr * z.maxPct) + rhr);
htmlRows += "