Determine your peak heart rate and training zones for optimal fitness.
Male
Female
Fox Formula (Standard)
Tanaka Formula (More Precise)
Gulati Formula (Women Only)
Your Estimated Maximum Heart Rate:
0BPM
BPM = Beats Per Minute
Zone
Intensity
Heart Rate Range
Understanding Your Maximum Heart Rate (MHR)
Your Maximum Heart Rate (MHR) is the highest number of beats per minute your heart can reach under maximum stress. In the UK, athletes, gym-goers, and those rehabilitating from injury use MHR to tailor their cardiovascular training programmes. By knowing your limit, you can define specific training zones to ensure you are working at the correct intensity for your goals—whether that is fat loss, endurance, or peak performance.
The Formulas Used in This Calculator
There is no single "perfect" way to calculate MHR without a clinical stress test, but these common scientific formulas provide highly reliable estimates:
Fox Formula: The most common method (220 – Age). It is simple and widely used by the NHS and personal trainers.
Tanaka Formula: Research suggests this is more accurate for adults over the age of 40. The formula is 208 – (0.7 x Age).
Gulati Formula: Specifically developed for women to provide a more accurate reading, as the standard Fox formula often overestimates MHR for females. The formula is 206 – (0.88 x Age).
Training Zones Explained
Training at different percentages of your MHR yields different physiological benefits:
Zone 1 (50-60%): Very Light. Ideal for warm-ups, cool-downs, and active recovery.
Zone 2 (60-70%): Light. Known as the "fat-burning zone." Improves basic endurance and allows the body to become efficient at burning fat for fuel.
Zone 3 (70-80%): Moderate. The "aerobic zone." Improves cardiovascular capacity and strengthens the heart.
Zone 4 (80-90%): Hard. The "anaerobic zone." Increases lactate threshold and improves high-speed endurance.
Zone 5 (90-100%): Maximum. Sprint intervals. Only sustainable for very short periods; improves maximum speed and power.
Note: While calculators are excellent tools, individuals on certain medications (like beta-blockers) or those with underlying health conditions should consult a GP before starting a high-intensity exercise regime.
function calculateMHR() {
var age = parseFloat(document.getElementById('mhr_age').value);
var gender = document.getElementById('mhr_gender').value;
var formula = document.getElementById('mhr_formula').value;
var display = document.getElementById('mhr_display');
var resultSection = document.getElementById('mhr_result_section');
var zonesBody = document.getElementById('mhr_zones_body');
if (isNaN(age) || age 120) {
alert("Please enter a valid age between 1 and 120.");
return;
}
var mhr = 0;
// Logic for different formulas
if (formula === 'fox') {
mhr = 220 – age;
} else if (formula === 'tanaka') {
mhr = 208 – (0.7 * age);
} else if (formula === 'gulati') {
mhr = 206 – (0.88 * age);
}
mhr = Math.round(mhr);
display.innerText = mhr;
resultSection.style.display = 'block';
// Calculate Zones
var zones = [
{ name: "Zone 1", label: "Recovery/Warm-up", perc: "50-60%", class: "z1", min: 0.50, max: 0.60 },
{ name: "Zone 2", label: "Fat Burn/Endurance", perc: "60-70%", class: "z2", min: 0.60, max: 0.70 },
{ name: "Zone 3", label: "Aerobic/Fitness", perc: "70-80%", class: "z3", min: 0.70, max: 0.80 },
{ name: "Zone 4", label: "Anaerobic/Performance", perc: "80-90%", class: "z4", min: 0.80, max: 0.90 },
{ name: "Zone 5", label: "Maximum Effort", perc: "90-100%", class: "z5", min: 0.90, max: 1.00 }
];
var zonesHtml = "";
for (var i = 0; i < zones.length; i++) {
var zMin = Math.round(mhr * zones[i].min);
var zMax = Math.round(mhr * zones[i].max);
zonesHtml += "
";
zonesHtml += "
" + zones[i].name + "
";
zonesHtml += "
" + zones[i].label + " (" + zones[i].perc + ")
";
zonesHtml += "
" + zMin + " – " + zMax + " BPM
";
zonesHtml += "
";
}
zonesBody.innerHTML = zonesHtml;
// Smooth scroll to result
resultSection.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
}