Heart Rate Range Calculator

Heart Rate Range Calculator

Calculate your optimal training zones using the Karvonen formula

Measure this while sitting quietly.

Your Vital Stats

Estimated Maximum Heart Rate: BPM

Heart Rate Reserve (HRR): BPM

Target Heart Rate Zones

Intensity Zone HR Range (BPM) Purpose
Zone 1: Very Light (50-60%) Warm-up & Recovery
Zone 2: Light (60-70%) Fat Burning & Endurance
Zone 3: Moderate (70-80%) Aerobic Capacity
Zone 4: Hard (80-90%) Anaerobic Threshold
Zone 5: Maximum (90-100%) Peak Performance

Understanding Your Training Zones

Using a heart rate range calculator is essential for athletes and fitness enthusiasts who want to optimize their workouts. Instead of guessing how hard you are working, tracking your beats per minute (BPM) ensures you are training in the correct zone for your specific goals.

The Karvonen Formula Explained

Unlike simple age-based formulas, this calculator uses the Karvonen Method. This formula is considered more accurate because it incorporates your Resting Heart Rate (RHR) to determine your Heart Rate Reserve. This personalizes the ranges to your current cardiovascular fitness level.

Formula: Target HR = ((Max HR − Resting HR) × % Intensity) + Resting HR

What Do the Zones Mean?

  • Zone 1 (50-60%): Ideal for active recovery and beginners. It improves overall health but doesn't strain the body.
  • Zone 2 (60-70%): Often called the "Fat Burning Zone." It builds basic endurance and burns a higher percentage of calories from fat.
  • Zone 3 (70-80%): Improves aerobic power. This is the "sweet spot" for improving cardiovascular health and stamina.
  • Zone 4 (80-90%): This is high-intensity training. It increases your anaerobic threshold and helps you sustain faster speeds for longer.
  • Zone 5 (90-100%): Maximum effort. Only sustainable for short bursts, typically used in sprint interval training.

Example Calculation

If you are 40 years old with a resting heart rate of 70 BPM:

  1. Max HR: 220 – 40 = 180 BPM.
  2. HR Reserve: 180 – 70 = 110 BPM.
  3. 70% Intensity Calculation: (110 x 0.70) + 70 = 147 BPM.
function calculateHRRange() { var age = parseFloat(document.getElementById("hr_age").value); var restingHR = parseFloat(document.getElementById("hr_resting").value); if (isNaN(age) || age 120) { alert("Please enter a valid age."); return; } if (isNaN(restingHR) || restingHR 150) { alert("Please enter a valid resting heart rate (typical range 30-150)."); return; } // Step 1: Calculate Max HR (Standard Formula) var maxHR = 220 – age; // Step 2: Calculate HR Reserve (HRR) var hrr = maxHR – restingHR; if (hrr <= 0) { alert("Resting heart rate cannot be higher than your maximum heart rate. Please check your inputs."); return; } // Function to calculate specific target using Karvonen function getKarvonen(percentage) { return Math.round((hrr * percentage) + restingHR); } // Zone Calculations var z1_low = getKarvonen(0.50); var z1_high = getKarvonen(0.60); var z2_low = getKarvonen(0.60); var z2_high = getKarvonen(0.70); var z3_low = getKarvonen(0.70); var z3_high = getKarvonen(0.80); var z4_low = getKarvonen(0.80); var z4_high = getKarvonen(0.90); var z5_low = getKarvonen(0.90); var z5_high = maxHR; // Display Results document.getElementById("res_max").innerHTML = maxHR; document.getElementById("res_reserve").innerHTML = hrr; document.getElementById("zone1").innerHTML = z1_low + " – " + z1_high + " BPM"; document.getElementById("zone2").innerHTML = z2_low + " – " + z2_high + " BPM"; document.getElementById("zone3").innerHTML = z3_low + " – " + z3_high + " BPM"; document.getElementById("zone4").innerHTML = z4_low + " – " + z4_high + " BPM"; document.getElementById("zone5").innerHTML = z5_low + " – " + z5_high + " BPM"; document.getElementById("hr_results").style.display = "block"; }

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