Heart Rate Zone Calculator
Find your training zones for optimal cardio workouts
Train smarter by knowing your heart rate zones. This calculator uses the Karvonen method to determine your 5 training zones based on age and resting heart rate for optimal cardio results.
Most common answer: A 30-year-old with a resting heart rate of 70 bpm has a max heart rate of 187 bpm. Fat-burning zone: 140–152 bpm. Aerobic zone: 152–163 bpm.
This calculator provides estimates for informational purposes only. It is not medical advice. Consult a healthcare professional before making health decisions.
Very light effort, recovery
Light effort, fat burning
Moderate effort, endurance
Hard effort, performance
Maximum effort, peak power
- Sit still for 5 minutes after waking up
- Place two fingers on your wrist or neck
- Count heartbeats for 60 seconds (or 30 seconds and multiply by 2)
- Repeat for 3 mornings and take the average
Heart Rate Zone Calculator
How to Use This Calculator
Enter your age and optionally your resting heart rate. The calculator computes your maximum heart rate and all 5 training zones using the Karvonen formula, which is more accurate than simple percentage-based methods.
What Are Heart Rate Zones?
Heart rate zones are ranges of heartbeats per minute that correspond to different exercise intensities. Training in different zones produces different physiological adaptations:
| Zone | % of HRR | Purpose | Duration |
|---|---|---|---|
| Zone 1 (Warm Up) | 50–60% | Recovery, warm-up | 20–40 min |
| Zone 2 (Fat Burn) | 60–70% | Fat oxidation, base fitness | 30–90 min |
| Zone 3 (Aerobic) | 70–80% | Cardiovascular endurance | 20–40 min |
| Zone 4 (Anaerobic) | 80–90% | Lactate threshold, speed | 5–20 min |
| Zone 5 (VO2 Max) | 90–100% | Peak power, sprints | 1–5 min |
The Karvonen Formula
Target HR = Resting HR + (Heart Rate Reserve × Intensity%)
Heart Rate Reserve (HRR) = Max HR − Resting HR. This method personalizes zones by accounting for your fitness level through resting heart rate.
How to Measure Resting Heart Rate
- Sit quietly for 5 minutes immediately after waking up.
- Place two fingers on the inside of your wrist or on your neck.
- Count heartbeats for 60 seconds, or count for 30 seconds and multiply by 2.
- Repeat for 3 consecutive mornings and average the results.
Sources
- Tanaka, H. et al. (2001). Age-predicted maximal heart rate revisited. JACC, 37(1), 153–156.
- Karvonen, M.J. et al. (1957). The effects of training on heart rate.
- American Heart Association — Target Heart Rates Chart
Medical disclaimer: Consult your doctor before starting a new exercise program, especially if you have heart conditions or are on medications that affect heart rate.
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Frequently Asked Questions
Zone 2 (60-70% of heart rate reserve) is considered the "fat burning zone" because the body uses a higher percentage of fat for fuel at this intensity. However, higher-intensity zones burn more total calories per minute. For weight loss, Zone 3-4 intervals mixed with Zone 2 steady-state cardio is most effective overall.
This calculator uses the Tanaka formula: Max HR = 208 - (0.7 x age), which is more accurate than the traditional 220 - age formula. For a 30-year-old: 208 - (0.7 x 30) = 187 bpm. The only truly accurate way to measure max HR is through a graded exercise test with a doctor.
The Karvonen method calculates target heart rate zones using your Heart Rate Reserve (HRR), which is max HR minus resting HR. This personalizes the zones for your fitness level. Formula: Target HR = Resting HR + (HRR x intensity%). A fit person with a low resting HR will have wider zones than someone who is less fit.
A normal resting heart rate for adults is 60-100 bpm. Well-trained athletes often have resting rates of 40-60 bpm. A lower resting heart rate generally indicates better cardiovascular fitness. Factors that increase resting HR include stress, caffeine, illness, medications, and dehydration. Measure first thing in the morning for accuracy.
Zone 1 (warm up): 5-10 minutes. Zone 2 (fat burn): 30-90 minutes for endurance base building. Zone 3 (aerobic): 20-40 minutes for cardiovascular improvement. Zone 4 (anaerobic): 5-20 minutes total in intervals. Zone 5 (VO2 max): 1-5 minutes total in short bursts. Most training should be in Zones 1-2 (about 80% of total time).
Several factors can elevate heart rate above predicted zones: dehydration, heat, caffeine, stress, illness, sleep deprivation, or being new to exercise. Medications like beta-blockers lower heart rate artificially. If your heart rate consistently runs high, your max HR may be above average. Consult a doctor if concerned.
Heart rate zones are primarily designed for cardiovascular exercise. During strength training, heart rate spikes briefly during exertion and drops during rest periods, making sustained zone training impractical. However, circuit training and metabolic conditioning workouts can effectively use Zones 3-4. Rest period length can be guided by letting HR drop to Zone 2.
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