Based on the Karvonen formula (if Resting HR provided) or Standard Max HR formula.
Zone
Intensity
Target Range (BPM)
Benefit
How to Use This BPM Calculator
Understanding your heart rate is crucial for monitoring cardiovascular health and optimizing fitness training. This calculator serves two main functions: converting a short manual pulse count into a Beats Per Minute (BPM) reading, and calculating your target heart rate zones based on your age.
How to take your pulse manually: Place two fingers (index and middle) on your wrist (radial artery) or the side of your neck (carotid artery). Count the beats you feel for a specific timeframe (usually 10 or 15 seconds) and enter that number above.
Understanding Heart Rate Zones
Training at different intensities triggers different metabolic adaptations in your body. We calculate these zones using your Maximum Heart Rate (MHR). If you provide your Resting Heart Rate, we use the Karvonen Formula for higher accuracy, which accounts for your heart rate reserve.
Zone 1 (50-60%): Very light activity, warm-up, and recovery. Good for beginners.
Zone 2 (60-70%): Fat burning zone. The body becomes efficient at metabolizing fat. Ideal for endurance.
Zone 3 (70-80%): Aerobic zone. Improves cardiovascular system and stamina.
Zone 4 (80-90%): Anaerobic zone. Improves VO2 Max and lactic acid tolerance. Hard effort.
Zone 5 (90-100%): Maximum effort. Only sustainable for very short bursts. Increases power and speed.
Why Monitor Your Resting Heart Rate?
Your Resting Heart Rate (RHR) is a strong indicator of your overall fitness level. A normal RHR for adults ranges from 60 to 100 beats per minute. Highly trained athletes may see readings as low as 40 to 60 BPM. Tracking this over time can show improvements in cardiovascular efficiency or signal potential overtraining or illness.
Disclaimer
This calculator is for informational and educational purposes only. The "220 minus age" formula is a general estimate. For precise medical advice or before starting a new exercise program, consult a healthcare professional or a cardiologist.
function calculateBPM() {
// 1. Get Inputs
var countTime = document.getElementById('countTime').value;
var beatsCounted = document.getElementById('beatsCounted').value;
var userAge = document.getElementById('userAge').value;
var restingHR = document.getElementById('restingHR').value;
// Result Elements
var displayBPM = document.getElementById('displayBPM');
var displayMaxHR = document.getElementById('displayMaxHR');
var resultsArea = document.getElementById('results-area');
var zoneTableBody = document.getElementById('zoneTableBody');
// Validation Flags
var hasPulseData = (beatsCounted !== "" && !isNaN(beatsCounted));
var hasAgeData = (userAge !== "" && !isNaN(userAge));
var hasRestingData = (restingHR !== "" && !isNaN(restingHR));
if (!hasPulseData && !hasAgeData) {
alert("Please enter either your pulse count OR your age to calculate.");
return;
}
// Show Results Area
resultsArea.style.display = "block";
// — Logic Part 1: Current BPM Calculation —
if (hasPulseData) {
var timeMultiplier = 60 / parseFloat(countTime);
var currentBPM = parseFloat(beatsCounted) * timeMultiplier;
displayBPM.innerHTML = Math.round(currentBPM);
} else {
displayBPM.innerHTML = "–";
}
// — Logic Part 2: Max HR & Zones Calculation —
if (hasAgeData) {
var age = parseFloat(userAge);
var maxHR = 220 – age; // Tanaka formula is 208 – (0.7 * age), but 220-age is standard for general calculators
displayMaxHR.innerHTML = maxHR;
// Prepare for Zone Calculation
// If Resting HR is provided, use Karvonen: Target = ((Max – Resting) * %) + Resting
// If not, use Standard: Target = Max * %
var rhr = hasRestingData ? parseFloat(restingHR) : 0;
var useKarvonen = hasRestingData;
// Helper function for calculation
function getZoneLimit(percent) {
if (useKarvonen) {
var reserve = maxHR – rhr;
return Math.round((reserve * percent) + rhr);
} else {
return Math.round(maxHR * percent);
}
}
// Zone Data Array
var zones = [
{ name: "Zone 1: Warm Up", percentLow: 0.50, percentHigh: 0.60, class: "zone-row-1", benefit: "Recovery, Warm up" },
{ name: "Zone 2: Fat Burn", percentLow: 0.60, percentHigh: 0.70, class: "zone-row-2", benefit: "Basic Endurance, Fat Burning" },
{ name: "Zone 3: Aerobic", percentLow: 0.70, percentHigh: 0.80, class: "zone-row-3", benefit: "Cardiovascular Fitness" },
{ name: "Zone 4: Anaerobic", percentLow: 0.80, percentHigh: 0.90, class: "zone-row-4", benefit: "High Speed Endurance" },
{ name: "Zone 5: Maximum", percentLow: 0.90, percentHigh: 1.00, class: "zone-row-5", benefit: "Max Power & Speed" }
];
// Build Table HTML
var tableHTML = "";
for (var i = 0; i < zones.length; i++) {
var low = getZoneLimit(zones[i].percentLow);
var high = getZoneLimit(zones[i].percentHigh);
tableHTML += "