Heart Rate Zone Calculator
Free Heart rate zone Calculator for human physiology. Enter variables to compute results with formulas and detailed steps.
Reviewed by Daniel Agrici, Founder & Lead Developer
Formula
Target HR = ((Max HR - Resting HR) x %Intensity) + Resting HR
This is the Karvonen formula (Heart Rate Reserve method). Max HR is estimated as 220 - age (Fox formula) or can be measured directly. Resting HR should be measured in the morning before rising. The result gives personalized training zones that account for individual fitness levels, unlike simple percentage-of-max methods.
Worked Examples
Example 1: 30-Year-Old Runner Training Zones
Problem:A 30-year-old with resting heart rate of 60 bpm wants to know their training zones using the Karvonen method.
Solution:Max HR (Fox) = 220 - 30 = 190 bpm\nHeart Rate Reserve = 190 - 60 = 130 bpm\nZone 1: (130 x 0.50) + 60 to (130 x 0.60) + 60 = 125-138 bpm\nZone 2: (130 x 0.60) + 60 to (130 x 0.70) + 60 = 138-151 bpm\nZone 3: (130 x 0.70) + 60 to (130 x 0.80) + 60 = 151-164 bpm\nZone 4: (130 x 0.80) + 60 to (130 x 0.90) + 60 = 164-177 bpm\nZone 5: (130 x 0.90) + 60 to 190 = 177-190 bpm
Result:Z1: 125-138 | Z2: 138-151 | Z3: 151-164 | Z4: 164-177 | Z5: 177-190 bpm
Example 2: Sedentary 50-Year-Old Starting Exercise
Problem:A 50-year-old with resting heart rate of 78 bpm wants safe exercise zones.
Solution:Max HR (Fox) = 220 - 50 = 170 bpm\nHeart Rate Reserve = 170 - 78 = 92 bpm\nZone 1: (92 x 0.50) + 78 to (92 x 0.60) + 78 = 124-133 bpm\nZone 2: (92 x 0.60) + 78 to (92 x 0.70) + 78 = 133-142 bpm\nRecommendation: Start with Zone 1-2 for first 4-6 weeks.
Result:Z1: 124-133 | Z2: 133-142 bpm — Safe starting range for beginners
Frequently Asked Questions
What are heart rate training zones?
Heart rate training zones divide your exercise intensity into five ranges based on percentage of your maximum heart rate (MHR). Each zone triggers different physiological adaptations. Zone 1 (50-60% MHR) is recovery, Zone 2 (60-70%) is fat burning and aerobic base, Zone 3 (70-80%) is aerobic endurance, Zone 4 (80-90%) is lactate threshold, and Zone 5 (90-100%) is maximum effort/VO2 max. Training in different zones on different days (called polarized training) produces better results than always training at moderate intensity. Most endurance athletes spend 80% of training time in Zones 1-2 and 20% in Zones 4-5.
How is maximum heart rate calculated?
The most common formula is the Fox formula: MHR = 220 - age. However, this has a standard deviation of 10-12 bpm, meaning your actual MHR could be 10-12 beats higher or lower. The Tanaka formula (208 - 0.7 x age) is considered more accurate for older adults. The Gulati formula (206 - 0.88 x age) was developed specifically for women. The most accurate method is a graded exercise test performed in a clinical setting. If you know your actual max heart rate from a fitness test or race, use that value instead of any formula for the most accurate training zones.
How do I measure my resting heart rate?
Measure your resting heart rate first thing in the morning before getting out of bed, ideally after a good night of sleep. Place two fingers on the inside of your wrist (radial pulse) or on the side of your neck (carotid pulse) and count beats for 60 seconds. Repeat for 3-5 consecutive mornings and take the average. A lower resting heart rate generally indicates better cardiovascular fitness. Average resting HR is 60-100 bpm, well-trained athletes may have 40-60 bpm, and elite endurance athletes can have below 40 bpm. Factors that raise resting HR include stress, illness, dehydration, caffeine, and poor sleep.
Which heart rate zone is best for weight loss?
While Zone 2 (60-70%) is often called the \"fat-burning zone\" because the highest percentage of calories come from fat, total calorie burn matters more for weight loss. Higher-intensity zones (3-4) burn more total calories per minute, including more total fat calories despite a lower percentage from fat. For example, 30 minutes in Zone 2 might burn 200 calories (50% from fat = 100 fat calories), while 30 minutes in Zone 4 burns 400 calories (35% from fat = 140 fat calories). The best approach combines Zone 2 sessions for volume with Zone 4 intervals for efficiency, plus strength training to maintain muscle mass.
References
Reviewed by Daniel Agrici, Founder & Lead Developer · Editorial policy