Heart Rate Zone Calculator

Training in specific heart rate zones optimizes cardiovascular fitness, fat burn, and endurance:

• Zone 1 (50-60%): Warm-up & active recovery.

• Zone 2 (60-70%): Endurance building & primary fat oxidation.

• Zone 3 (70-80%): Aerobic capacity & stamina enhancement.

• Zone 4 (80-90%): Anaerobic threshold & high-intensity performance.

• Zone 5 (90-100%): Maximum speed & power intervals.

To use the Heart Rate Zone Calculator, enter your Unit System, Biological Sex, Age and other values. The calculator instantly computes Calculated Result, Health Assessment Category and more. Results update in real time as you change any input — no submit button needed.

How to Use This Calculator

Enter your Unit System — select from Metric (kg, cm), Imperial (lbs, inches), Biological Sex — select from Male, Female, Age (e.g. 30 in years), Body Weight (e.g. 70 in kg / lbs), Height (e.g. 175 in cm / inches), and Activity Level — select from Sedentary (desk job), Lightly Active (1-3 days/wk), Moderately Active (3-5 days/wk). Results update instantly — no submit button needed. Use metric or imperial units as labeled. For the most accurate result, measure height and weight in the morning without shoes.

The Formula

Max Heart Rate (HRmax) = 220 - Age. Karvonen Formula: Target HR = [(HRmax - Resting HR) x %Intensity] + Resting HR.

Worked Example

30-year-old athlete with resting HR of 60 bpm. HRmax = 190 bpm. Heart Rate Reserve = 130 bpm. Zone 2 (Fat Burn, 60-70%): 138 - 151 bpm. Zone 3 (Aerobic, 70-80%): 151 - 164 bpm.

Understanding Your Result

The 220 – age formula for maximum heart rate (MHR) has a standard deviation of ±10–12 bpm — meaning actual MHR varies widely. Zone 2 training (60–70% MHR) builds aerobic base and fat oxidation efficiency. Zone 4–5 (80–95% MHR) builds VO2 max and lactate threshold but requires adequate recovery. Resting heart rate below 60 bpm is common in trained athletes; above 100 bpm at true rest (tachycardia) warrants medical evaluation if persistent.