Estimate your Max HR (MHR) and Calculate Training Zones
Fox Formula (Standard: 220 – Age)
Tanaka Formula (208 – 0.7 × Age)
Gulati Formula (Women: 206 – 0.88 × Age)
Haskell & Fox (Similar to Standard)
Estimated Maximum Heart Rate0 BPM
Target Heart Rate Training Zones
Zone
Intensity
Range (BPM)
Benefit
Understanding Your Maximum Heart Rate
Knowing your Maximum Heart Rate (MHR) is the cornerstone of effective cardiovascular training. By identifying your upper limit, you can define specific heart rate zones to tailor your workouts for fat burning, endurance, or peak performance.
Which Formula Should You Use?
While the standard formula is widely used, researchers have developed variations to improve accuracy for different populations:
Fox Formula (220 – Age): The most common and simplest method. It provides a general baseline but can overestimate MHR for younger people and underestimate it for older adults.
Tanaka Formula (208 – 0.7 × Age): Considered more accurate for healthy adults of varying ages. It smoothens the age-related decline in heart rate.
Gulati Formula (206 – 0.88 × Age): specifically researched for women, as the standard formula often overestimates MHR for females.
Heart Rate Training Zones Explained
Once your MHR is calculated, your training intensity is broken down into five zones:
Zone 1 (50-60%): Very light activity, warm-up, and recovery.
Zone 2 (60-70%): Light training, builds endurance and burns fat.
Zone 3 (70-80%): Moderate aerobic activity, improves blood circulation and skeletal muscle efficiency.
Zone 4 (80-90%): Hard training, increases maximum performance capacity.
Zone 5 (90-100%): Maximum effort, develops speed and neuromuscular coordination.
Safety Note: This calculator provides estimates based on population averages. Genetic factors, medication, and fitness levels can cause your actual max heart rate to vary significantly. Always consult a physician before starting a high-intensity training program.
function calculateMaxRate() {
// 1. Get Inputs
var ageInput = document.getElementById('inputAge');
var formulaInput = document.getElementById('inputFormula');
var resultContainer = document.getElementById('mhrResultContainer');
var displayMHR = document.getElementById('displayMHR');
var formulaLabel = document.getElementById('formulaUsedLabel');
var zoneTableBody = document.getElementById('zoneTableBody');
var age = parseFloat(ageInput.value);
var formula = formulaInput.value;
// 2. Validation
if (isNaN(age) || age 120) {
alert("Please enter a valid age between 1 and 120.");
resultContainer.style.display = "none";
return;
}
// 3. Logic: Calculate Max HR based on formula
var mhr = 0;
var formulaText = "";
if (formula === 'fox') {
mhr = 220 – age;
formulaText = "Based on Fox Formula (220 – Age)";
} else if (formula === 'tanaka') {
mhr = 208 – (0.7 * age);
formulaText = "Based on Tanaka Formula (208 – 0.7 * Age)";
} else if (formula === 'gulati') {
mhr = 206 – (0.88 * age);
formulaText = "Based on Gulati Formula (206 – 0.88 * Age)";
} else if (formula === 'haskell') {
// Haskell is often cited similarly to Fox in general tools but technically derived differently.
// For this calculator, we use the simplified integer accepted value or the Fox standard.
mhr = 220 – age;
formulaText = "Based on Haskell & Fox";
}
// Round MHR to nearest integer
var finalMHR = Math.round(mhr);
// 4. Calculate Zones
// Zone 1: 50-60%
var z1_min = Math.round(finalMHR * 0.50);
var z1_max = Math.round(finalMHR * 0.60);
// Zone 2: 60-70%
var z2_min = Math.round(finalMHR * 0.60);
var z2_max = Math.round(finalMHR * 0.70);
// Zone 3: 70-80%
var z3_min = Math.round(finalMHR * 0.70);
var z3_max = Math.round(finalMHR * 0.80);
// Zone 4: 80-90%
var z4_min = Math.round(finalMHR * 0.80);
var z4_max = Math.round(finalMHR * 0.90);
// Zone 5: 90-100%
var z5_min = Math.round(finalMHR * 0.90);
var z5_max = finalMHR;
// 5. Update DOM
displayMHR.innerHTML = finalMHR + " BPM";
formulaLabel.innerText = formulaText;
// Build Table HTML
var tableHTML = `