Determine your optimal heart rate training zones to maximize your workout efficiency. This calculator uses both the standard Maximum Heart Rate method and the more accurate Karvonen Formula.
Enter this for the advanced Karvonen calculation.
—Max Heart Rate (bpm)
StandardFormula Used
Training Intensity Zones
Zone Intensity
Range (%)
Target Heart Rate
Understanding the Target Heart Rate Formula
Calculating your target heart rate is crucial for ensuring that you are exercising at an intensity that matches your fitness goals. Whether you want to burn fat, build endurance, or improve cardiovascular health, training in the specific heart rate zone allows you to get the most out of every minute of exercise.
The Standard Formula (Max Heart Rate)
The most basic method to estimate your target heart rate is based solely on your age. This method assumes a linear decline in maximum heart rate as you age.
MHR (Maximum Heart Rate) = 220 – Age
Once your MHR is calculated, your target zone is simply a percentage of this number. For example, a 50% intensity for a 40-year-old (MHR 180) would be 90 bpm.
The Karvonen Formula (Heart Rate Reserve)
For a more personalized result, exercise physiologists often use the Karvonen Formula. This method incorporates your Resting Heart Rate (RHR), which accounts for your individual fitness level. A lower resting heart rate usually indicates better cardiovascular fitness.
This formula calculates the "Heart Rate Reserve" first (the difference between your Max and Resting HR), applies the percentage to that reserve, and then adds the resting rate back in. This prevents the target from dropping below what your heart beats at rest.
Heart Rate Training Zones
Different intensity levels trigger different metabolic responses in the body:
Moderate Intensity (50-70%): Often called the "Fat Burn" or "Warm Up" zone. This is ideal for beginners, long-duration endurance training, and weight management. It utilizes fat as the primary fuel source.
Vigorous Intensity (70-85%): Known as the "Cardio" or "Aerobic" zone. This intensity improves cardiovascular capacity and respiratory health. It burns more calories per minute than moderate intensity but shifts fuel usage toward glycogen (carbohydrates).
Maximum Effort (85-100%): The "Peak" or "Anaerobic" zone. Sustainable only for short bursts (like sprinting). This improves speed and power but carries a higher risk of injury if not properly trained.
How to Measure Resting Heart Rate
To use the Karvonen formula effectively, measure your pulse before you get out of bed in the morning. Count the beats for 60 seconds. Do this for 3-5 days and take the average for the most accurate input.
Safety Considerations
The formulas provided are estimates for the general population. Factors such as medications (beta-blockers), genetics, and medical history can alter your actual maximum heart rate. Always consult a physician before starting a new exercise program, especially if you have a history of heart conditions.
function calculateTargetHeartRate() {
// 1. Get Inputs
var ageInput = document.getElementById('thrAge');
var rhrInput = document.getElementById('thrRHR');
var resultsDiv = document.getElementById('thrResults');
var displayMax = document.getElementById('displayMaxHR');
var displayMethod = document.getElementById('displayMethod');
var tableBody = document.getElementById('zonesTableBody');
var age = parseFloat(ageInput.value);
var rhr = parseFloat(rhrInput.value);
// 2. Validation
if (isNaN(age) || age 120) {
alert("Please enter a valid age between 1 and 120.");
return;
}
// 3. Calculation Logic
var maxHR = 220 – age;
var useKarvonen = false;
// Check if RHR is valid for Karvonen formula
if (!isNaN(rhr) && rhr > 30 && rhr < 200 && rhr < maxHR) {
useKarvonen = true;
}
// 4. Update Header Metrics
displayMax.innerHTML = Math.round(maxHR);
displayMethod.innerHTML = useKarvonen ? "Karvonen(More Accurate)" : "Standard(Age Based)";
// 5. Generate Zones
// Zones Definition: [Label, Min%, Max%]
var zones = [
{ label: "Very Light (Warm Up)", min: 0.50, max: 0.60 },
{ label: "Light (Fat Burn)", min: 0.60, max: 0.70 },
{ label: "Moderate (Aerobic)", min: 0.70, max: 0.80 },
{ label: "Hard (Anaerobic)", min: 0.80, max: 0.90 },
{ label: "Maximum (VO2 Max)", min: 0.90, max: 1.00 }
];
var htmlRows = "";
for (var i = 0; i < zones.length; i++) {
var z = zones[i];
var minBPM, maxBPM;
if (useKarvonen) {
// Formula: ((MaxHR – RHR) * %) + RHR
var hrr = maxHR – rhr;
minBPM = Math.round((hrr * z.min) + rhr);
maxBPM = Math.round((hrr * z.max) + rhr);
} else {
// Formula: MaxHR * %
minBPM = Math.round(maxHR * z.min);
maxBPM = Math.round(maxHR * z.max);
}
htmlRows += "