Target Heart Rate Calculator
Free Target Heart Rate Calculator using the Karvonen formula. Calculate your 5 heart rate training zones based on age and resting heart rate for optimal exercise intensity.
About This Calculator
Target heart rate zones help you train at the right intensity for your fitness goals. Whether you want to burn fat, improve cardiovascular endurance, build anaerobic capacity, or maximize athletic performance, knowing your personalized heart rate zones is essential for effective and safe training.
Our calculator uses the Tanaka formula (208 - 0.7 x age) to estimate your maximum heart rate, then applies the Karvonen formula to calculate five training zones based on your heart rate reserve (max HR minus resting HR). This approach is more accurate than simple percentage-of-max methods because it accounts for your individual fitness level.
Five Heart Rate Training Zones:
- Zone 1 - Very Light (50-60%): Warm-up, recovery, and cool-down. Improves overall circulation and prepares muscles for exercise.
- Zone 2 - Light (60-70%): Fat-burning zone. Builds aerobic endurance and improves the body's ability to use fat for fuel.
- Zone 3 - Moderate (70-80%): Cardiovascular training zone. Improves heart and lung capacity, the foundation of aerobic fitness.
- Zone 4 - Hard (80-90%): Anaerobic threshold zone. Increases lactate tolerance and improves high-intensity performance.
- Zone 5 - Maximum (90-100%): Sprint and maximum effort zone. Develops explosive speed and power, improves neuromuscular coordination.
Key Formulas:
- Max HR: 208 - 0.7 x age (Tanaka, 2001)
- Heart Rate Reserve (HRR): Max HR - Resting HR
- Target HR: (HRR x %Intensity) + Resting HR (Karvonen)
Frequently Asked Questions
How do I calculate my target heart rate zones?
Target heart rate zones are calculated using the Karvonen formula: Target HR = ((Max HR - Resting HR) x %Intensity) + Resting HR. Max HR is estimated as 208 - 0.7 x age (Tanaka formula). We calculate five zones: Very Light (50-60%), Light (60-70%), Moderate (70-80%), Hard (80-90%), and Maximum (90-100%). Enter your age and resting heart rate to get personalized zones.
What is the best heart rate zone for fat burning?
The fat-burning zone is Zone 2 (60-70% of heart rate reserve using the Karvonen formula). At this intensity, your body uses fat as its primary fuel source. However, total calories burned is higher at higher intensities. For maximum fat loss, combine Zone 2 steady-state cardio with higher-intensity Zone 3-4 intervals. The best approach is to train across multiple zones for overall fitness and metabolic health.
What is a normal resting heart rate?
A normal resting heart rate for adults ranges from 60-100 bpm. Well-trained athletes may have resting heart rates of 40-60 bpm. A lower resting heart rate generally indicates better cardiovascular fitness. Factors that can elevate resting heart rate include dehydration, stress, caffeine, illness, and lack of sleep. Measure your resting heart rate first thing in the morning before getting out of bed for most accurate results.
How accurate is the age-based max heart rate formula?
The Tanaka formula (208 - 0.7 x age) is more accurate than the traditional 220 - age formula, with a standard deviation of about 7-10 bpm. Individual max heart rate varies significantly due to genetics, fitness level, and medications. For most accurate results, a maximal exercise test with ECG monitoring provides your true max heart rate. Use the formula as a good starting point for zone training.
What is the Karvonen formula and why use it?
The Karvonen formula calculates target heart rate as: ((Max HR - Resting HR) x %Intensity) + Resting HR. It's more accurate than percentage-of-max formulas because it accounts for your resting heart rate and heart rate reserve (HRR). This personalizes the zones to your fitness level - a fit person with low resting HR will have different zone ranges than an unfit person with the same max HR.
How long should I train in each heart rate zone?
Zone 1 (Very Light): Use for warm-up (5-10 min) and cool-down (5 min). Zone 2 (Light): 30-60 minutes for endurance and fat burning. Zone 3 (Moderate): 20-40 minutes for cardiovascular fitness. Zone 4 (Hard): 5-15 minutes in intervals for anaerobic threshold. Zone 5 (Maximum): 30 seconds to 2 minutes in sprint intervals. Most balanced training programs include 80% low-intensity (Zones 1-2) and 20% high-intensity (Zones 4-5) work.
Can heart rate zones differ for running vs cycling?
Yes, heart rate zones can differ by activity. Running typically produces 5-10 bpm higher heart rates than cycling at the same perceived effort because it's weight-bearing. Swimming often shows 10-15 bpm lower max heart rates due to water temperature and body position. For multi-sport athletes, consider sport-specific zone testing or use perceived exertion (RPE) alongside heart rate for more accurate training.
How do I measure my resting heart rate accurately?
For most accurate resting heart rate: Measure first thing in the morning before getting out of bed, after at least 6 hours of quality sleep. Place your index and middle fingers on your neck (carotid artery) or wrist (radial artery). Count beats for 30 seconds and multiply by 2, or count for 60 seconds for more accuracy. Take measurements over 3-5 consecutive mornings and use the average. Avoid caffeine and alcohol the night before for consistent readings.