Heart Rate Zone Calculator Resting and Max

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Heart Rate Zone Calculator (Karvonen Method)

Your Personalized Results

Estimated Max Heart Rate: 0 BPM

Heart Rate Reserve (HRR): 0 BPM

Zone Intensity Target BPM Range Focus
Zone 1 50-60% Warm-up & Recovery
Zone 2 60-70% Fat Burn & Endurance
Zone 3 70-80% Aerobic/Stamina
Zone 4 80-90% Anaerobic/Performance
Zone 5 90-100% Sprints/Max Effort
function calculateHRZones() { var age = parseFloat(document.getElementById('hr_age').value); var rhr = parseFloat(document.getElementById('hr_resting').value); if (!age || !rhr || age <= 0 || rhr <= 0) { alert("Please enter a valid age and resting heart rate."); return; } // Formula: 220 – age is the standard for Max HR var maxHR = 220 – age; // Heart Rate Reserve (HRR) = Max HR – Resting HR var hrr = maxHR – rhr; if (hrr <= 0) { alert("Resting heart rate cannot be higher than maximum heart rate. Please check your inputs."); return; } // Karvonen Formula: Target HR = ((Max HR − Resting HR) × %Intensity) + Resting HR function getZoneRange(lowPct, highPct) { var low = Math.round((hrr * lowPct) + rhr); var high = Math.round((hrr * highPct) + rhr); return low + " – " + high + " BPM"; } document.getElementById('res_max_hr').innerText = maxHR; document.getElementById('res_hrr').innerText = hrr; document.getElementById('z1_range').innerText = getZoneRange(0.50, 0.60); document.getElementById('z2_range').innerText = getZoneRange(0.60, 0.70); document.getElementById('z3_range').innerText = getZoneRange(0.70, 0.80); document.getElementById('z4_range').innerText = getZoneRange(0.80, 0.90); document.getElementById('z5_range').innerText = getZoneRange(0.90, 1.00); document.getElementById('hr_results_container').style.display = 'block'; }

Understanding Heart Rate Training Zones

Training with a heart rate monitor is one of the most effective ways to track workout intensity and ensure you are meeting your fitness goals. This calculator uses the Karvonen Formula, which is widely considered more accurate than simple percentages because it accounts for your Resting Heart Rate (RHR).

The Five Training Zones

  • Zone 1 (50–60%): Very Light. Great for active recovery and warming up. It improves overall health but won't significantly boost athletic performance.
  • Zone 2 (60–70%): Light. This is the "Fat Burning Zone." It builds basic endurance and allows your body to become more efficient at burning fat for fuel.
  • Zone 3 (70–80%): Moderate. The aerobic zone. This improves your cardiovascular capacity and strengthens your heart and lungs.
  • Zone 4 (80–90%): Hard. The anaerobic zone. You will be breathing hard. This zone increases your lactate threshold and improves high-speed endurance.
  • Zone 5 (90–100%): Maximum. Reserved for short bursts of maximal effort. This improves peak performance and speed but can only be sustained for very short periods.

How to Find Your Resting Heart Rate

For the most accurate calculation, measure your resting heart rate in the morning, immediately after waking up and before getting out of bed. Count your pulse for 60 seconds or use a wearable fitness tracker to get your average RHR over several days.

Example Calculation

If a 40-year-old athlete has a resting heart rate of 60 BPM:

  1. Max HR: 220 – 40 = 180 BPM
  2. Heart Rate Reserve (HRR): 180 – 60 = 120 BPM
  3. Zone 2 (60%) Target: (120 × 0.60) + 60 = 132 BPM

By using the Karvonen method, the athlete ensures that their "light" workout is specifically tailored to their current level of cardiovascular fitness.

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