Heart Rate Zones Calculator

Heart-rate zone training ensures you are exercising at the right intensity for your goals, whether that is fat burning, aerobic endurance, or peak performance. This calculator determines your five training zones using either the percentage of max HR or the Karvonen (heart-rate reserve) method.

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What Are Heart Rate Zones?

Heart-rate zones divide your exercise intensity into five distinct ranges, each corresponding to different physiological adaptations. Training in the correct zone helps you target specific fitness outcomes such as fat oxidation, aerobic capacity, or anaerobic power. Using a heart-rate monitor removes the guesswork from your training and ensures you are working hard enough to improve, without overtraining.

Maximum heart rate (MHR) is the highest number of beats per minute your heart can achieve during all-out effort. The most common estimation formula is 220 minus your age, though individual variation can be significant.

The Five Zones

Zone% of Max HRIntensityPrimary Benefit
Zone 150 – 60%Very LightRecovery, warm-up
Zone 260 – 70%LightBase endurance, fat burning
Zone 370 – 80%ModerateAerobic fitness, stamina
Zone 480 – 90%HardAnaerobic threshold, speed
Zone 590 – 100%MaximumPeak power, VO2 max

Karvonen Method (Heart Rate Reserve)

The Karvonen method provides more personalized zones by factoring in your resting heart rate:

Target HR = ((MHR − Resting HR) × % Intensity) + Resting HR

This approach is considered more accurate because it accounts for your current fitness level via resting heart rate.

Limitations

The 220 minus age formula can be off by 10-20 beats per minute for some individuals. If possible, determine your true max heart rate through a supervised max-effort test. Heart rate can also be affected by caffeine, dehydration, altitude, and stress. Use heart-rate zones as guidelines and combine them with perceived exertion for the most reliable training feedback. Consult a physician before starting high-intensity training, especially if you have cardiovascular concerns.

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Frequently Asked Questions

How do I find my maximum heart rate?
The simplest estimate is 220 minus your age, but this can vary by 10-20 bpm. A more accurate method is a graded exercise test supervised by a healthcare professional. Field tests like a 3-minute all-out effort on a track can also provide a closer estimate for experienced athletes.
Is the fat-burning zone really the best for losing fat?
While Zone 2 does burn a higher percentage of calories from fat, higher-intensity zones burn more total calories per minute. For overall fat loss, total calorie expenditure matters more than the fuel source. A mix of Zone 2 endurance and Zone 4 interval training is most effective.
What is the Karvonen method?
The Karvonen method calculates target heart rate using heart-rate reserve (max HR minus resting HR). It is more personalized than the straight percentage method because it accounts for your resting heart rate, which reflects your cardiovascular fitness. Fitter individuals have lower resting heart rates.
How long should I train in each zone?
A common distribution is 80% of training time in Zones 1-2 (easy) and 20% in Zones 3-5 (moderate to hard). This polarized approach is used by elite endurance athletes to build a strong aerobic base while incorporating enough intensity for performance gains.
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