Heart Rate Burning Zone Calculator

Heart Rate Burning Zone Calculator

Your Results

Estimated Maximum Heart Rate: 0 BPM

🔥 Fat Burning Zone (60% – 70%)

0 – 0 BPM

Best for weight loss and building aerobic base.

❤️ Cardio / Aerobic Zone (70% – 85%)

0 – 0 BPM

Best for cardiovascular endurance and heart health.

⚡ Peak Performance (85% – 100%)

0 – 0 BPM

High intensity. Best for speed and performance (short bursts).

function calculateZones() { var age = parseFloat(document.getElementById('age').value); var rhr = parseFloat(document.getElementById('restingHR').value); if (isNaN(age) || age 120) { alert("Please enter a valid age."); return; } if (isNaN(rhr) || rhr 150) { alert("Please enter a valid resting heart rate (usually 40-100 BPM)."); return; } // MHR using Hunt Formula (more accurate than 220-age) var mhr = Math.round(211 – (0.64 * age)); // Karvonen Formula: Target HR = ((MHR – RHR) × %Intensity) + RHR var hrr = mhr – rhr; // Heart Rate Reserve var fatLow = Math.round((hrr * 0.60) + rhr); var fatHigh = Math.round((hrr * 0.70) + rhr); var cardioLow = Math.round((hrr * 0.70) + rhr); var cardioHigh = Math.round((hrr * 0.85) + rhr); var peakLow = Math.round((hrr * 0.85) + rhr); var peakHigh = mhr; document.getElementById('mhr-display').innerText = mhr; document.getElementById('fat-burn-low').innerText = fatLow; document.getElementById('fat-burn-high').innerText = fatHigh; document.getElementById('cardio-low').innerText = cardioLow; document.getElementById('cardio-high').innerText = cardioHigh; document.getElementById('peak-low').innerText = peakLow; document.getElementById('peak-high').innerText = peakHigh; document.getElementById('results-area').style.display = 'block'; }

---

What is the Fat Burning Heart Rate Zone?

The "fat burning zone" refers to a specific intensity of exercise where your body primarily uses stored fat for fuel instead of carbohydrates. This zone typically occurs when your heart rate is between 60% and 70% of its maximum capacity. In this state, the body can take in enough oxygen to oxidize fat efficiently.

The Karvonen Formula Explained

This calculator uses the Karvonen Method, which is widely considered more accurate than the standard "220 minus age" formula. The Karvonen formula incorporates your Resting Heart Rate (RHR) to determine your Heart Rate Reserve. This personalizes the zones based on your current fitness level.

• Max Heart Rate (MHR): We use the Hunt formula (211 – 0.64 × age) for better accuracy across different age groups.
• Heart Rate Reserve (HRR): Calculated by subtracting your resting heart rate from your maximum.
• Target Range: Calculated by multiplying the HRR by the target intensity and adding back the resting heart rate.

Heart Rate Zone Breakdown

Zone	Intensity	Benefit
Warm Up	50-60%	Metabolism recovery and light warm up.
Fat Burn	60-70%	Weight loss and endurance base building.
Aerobic	70-85%	Cardiovascular fitness and stamina.
Anaerobic	85-100%	Speed, power, and maximum performance.

Practical Example

Imagine a 40-year-old individual with a resting heart rate of 70 BPM. Using the Hunt Formula, their estimated max heart rate is 185 BPM. Their fat-burning zone (60-70%) would sit between 139 and 151 BPM. To lose weight effectively, they should maintain their heart rate in this range during long walks, steady cycling, or light jogging for 30-60 minutes.

Important Considerations

While the fat-burning zone is excellent for long-term weight management, higher intensity "Cardio" zones burn more total calories in a shorter amount of time. A balanced fitness plan often includes 70-80% of training in the lower zones and 20% in higher intensity zones. Always consult with a healthcare professional before starting a new vigorous exercise program.