How to Find Target Heart Rate Calculator

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Target Heart Rate Calculator

50% – Very Light (Warm up) 60% – Light (Fat Burn) 70% – Moderate (Aerobic/Cardio) 80% – Hard (Anaerobic) 90% – Maximum (Sprints)
Your Results
Max Heart Rate (MHR)
—
BPM
Heart Rate Reserve (HRR)
—
BPM
Target Heart Rate
—
BPM
function calculateTHR() { var age = parseFloat(document.getElementById('age').value); var rhr = parseFloat(document.getElementById('restingHR').value); var intensity = parseFloat(document.getElementById('intensity').value) / 100; var resultsArea = document.getElementById('resultsArea'); if (isNaN(age) || age 120) { alert('Please enter a valid age.'); return; } if (isNaN(rhr) || rhr 200) { alert('Please enter a valid resting heart rate (usually between 40-100 BPM).'); return; } // Fox Formula for MHR var mhr = 220 – age; // Karvonen Formula var hrr = mhr – rhr; var thr = (hrr * intensity) + rhr; document.getElementById('mhrDisplay').innerText = Math.round(mhr); document.getElementById('hrrDisplay').innerText = Math.round(hrr); document.getElementById('thrDisplay').innerText = Math.round(thr); resultsArea.style.display = 'block'; }

How to Find and Use Your Target Heart Rate

Understanding how to find your target heart rate (THR) is essential for anyone looking to maximize the efficiency of their workouts. Whether you are training for a marathon or trying to lose weight, monitoring your heart rate ensures you are working hard enough to see results without overexerting yourself.

What is the Karvonen Formula?

This calculator uses the Karvonen Formula, which is considered more accurate than simple calculations because it takes your Resting Heart Rate (RHR) into account. The formula follows these steps:

  1. Max Heart Rate (MHR): 220 – Age.
  2. Heart Rate Reserve (HRR): MHR – Resting Heart Rate.
  3. Target Heart Rate: (HRR × Intensity%) + Resting Heart Rate.

Understanding Intensity Zones

Different fitness goals require different intensity levels. Here is a breakdown of what the percentages mean for your body:

  • 50% – 60%: Moderate Activity. Ideal for warm-ups, cool-downs, and beginner fitness levels. Helps with basic health and recovery.
  • 60% – 70%: Fat Burning Zone. This zone uses a higher percentage of fat for fuel. It is sustainable for longer durations.
  • 70% – 80%: Aerobic/Cardio Zone. This improves cardiovascular endurance and strengthens the heart and lungs.
  • 80% – 90%: Anaerobic Zone. Used for high-intensity interval training (HIIT). Increases your "lactate threshold" and speed.

Practical Example

Let's say a 35-year-old individual has a resting heart rate of 70 BPM and wants to work out at a moderate 70% intensity:

  • Max Heart Rate: 220 – 35 = 185 BPM
  • Heart Rate Reserve: 185 – 70 = 115 BPM
  • Calculation: (115 × 0.70) + 70 = 80.5 + 70
  • Target Heart Rate: ~151 BPM

How to Measure Your Resting Heart Rate

To get the most accurate result from this calculator, measure your RHR when you first wake up in the morning before getting out of bed. Place two fingers on your wrist (radial pulse) or neck (carotid pulse), count the beats for 60 seconds, or count for 15 seconds and multiply by 4.

Disclaimer: This calculator is for educational purposes only. Always consult with a physician before starting a new exercise regimen, especially if you have underlying health conditions or are taking medication that affects heart rate.

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