Heart Rate Training Zone Calculator
Structured training based on heart rate zones is one of the most effective ways to improve cardiovascular fitness and control training load. This calculator produces a five-zone training table using two methods. The standard method calculates zones as simple percentages of your maximum heart rate, estimated from age using the formula 220 minus age. The Karvonen (heart rate reserve) method is more individualised: it calculates zones using the difference between your maximum and resting heart rate, then scales each zone relative to that reserve. Enter your age and resting heart rate (measured after waking), or override with a known measured maximum heart rate. The calculator returns a complete zone table in beats per minute for both methods, the purpose of each zone, and guidance on which zone to use for fat burning, aerobic base, and VO2max development.
Max HR: -- bpm | Zone 2 (aerobic): -- bpm
Your training zones
| Zone | Name | % Max HR | Standard (bpm) | Karvonen (bpm) | Purpose |
|---|---|---|---|---|---|
| Z1 | Recovery / very light | 50 to 60% | -- | -- | Active recovery, warm-up, cool-down. Primarily fat metabolism. Very easy conversational pace. |
| Z2 | Aerobic / easy | 60 to 70% | -- | -- | Aerobic base building, fat burning zone, long slow distance. Sustainable for hours. |
| Z3 | Aerobic / moderate | 70 to 80% | -- | -- | Improved aerobic efficiency, tempo runs. Breathing is harder but still rhythmic. |
| Z4 | Anaerobic / hard | 80 to 90% | -- | -- | Lactate threshold improvement, interval training. Difficult to maintain conversation. |
| Z5 | Maximum / sprint | 90 to 100% | -- | -- | VO2max development, sprint intervals. Maximum effort. Only sustainable for seconds to 2 minutes. |
How training zones are calculated
Standard method:
Max HR = 220 - age (or measured value)
Zone lower = Max HR x zone_low_pct
Zone upper = Max HR x zone_high_pct
Karvonen (heart rate reserve) method:
HRR = Max HR - Resting HR
Zone lower = (HRR x zone_low_pct) + Resting HR
Zone upper = (HRR x zone_high_pct) + Resting HR
Worked example
Age 30, resting HR 60 bpm (max HR = 190 bpm, HRR = 130 bpm):
- Zone 2 standard: 190 x 0.60 to 190 x 0.70 = 114 to 133 bpm
- Zone 2 Karvonen: (130 x 0.60 + 60) to (130 x 0.70 + 60) = 138 to 151 bpm
The Karvonen zones are typically higher than standard zones for a given percentage, because they account for the elevated baseline (resting HR). This makes Karvonen more appropriate for athletes with low resting heart rates.
Which zone should I train in?
- Zone 1: Recovery days and warm-up. Do not skip this; it accelerates recovery between hard sessions.
- Zone 2: The foundation of aerobic fitness. Most endurance athletes aim for 70 to 80 percent of total training volume in Zone 2.
- Zone 3: Often called "no man's land" because it is too hard for easy recovery and too easy for maximum adaptation. Use sparingly.
- Zone 4: Lactate threshold work. Typical: 20 to 40 minute tempo runs or 4 to 8 minute intervals. High adaptation stimulus.
- Zone 5: Short, maximal efforts. VO2max intervals (30 sec to 4 min). Only 1 to 2 sessions per week maximum.
Training zone calculator: frequently asked questions
What are heart rate training zones?
Heart rate training zones divide the intensity spectrum from rest to maximum effort into bands. The 5-zone system used by the American College of Sports Medicine (ACSM) runs from Zone 1 (very light, 50 to 60 percent of max HR, for recovery) through Zone 5 (maximum, 90 to 100 percent of max HR, for sprint work and VO2max development). Training in different zones targets different physiological adaptations such as fat oxidation, aerobic base, lactate threshold, and anaerobic power.
What is the Karvonen formula?
The Karvonen formula calculates target heart rate using heart rate reserve (HRR), which is the difference between maximum heart rate and resting heart rate. The formula is: Target HR = ((Max HR - Resting HR) x Zone%) + Resting HR. Because it accounts for individual resting HR, the Karvonen method is more personalised than simple max-HR percentage zones, especially for those with low or high resting heart rates.
Which zone is best for fat burning?
Zone 2 (60 to 70 percent of max HR) is often called the fat-burning zone because fat oxidation is highest as a proportion of total energy at moderate intensities. However, total calories burned increases with intensity. Higher zones burn more total calories per minute. For long-term fat loss, the most effective approach combines consistent Zone 2 training with higher-intensity sessions for calorie burn, not exclusive Zone 2 work.
How accurate is the 220 minus age max HR formula?
The 220 minus age formula is a population average with significant individual variation. Research published in the Journal of the American College of Cardiology shows standard deviation of approximately 10 to 12 beats per minute around the predicted value. Roughly two-thirds of people fall within 10 to 12 bpm of the formula prediction. For precise training, a graded exercise test (GXT) administered by a qualified exercise physiologist gives an actual measured max HR.
Can I manually enter my max HR if I know it?
Yes. This calculator includes a manual max HR override field. If you have had a graded exercise test or know your measured max HR from a hard race or effort, enter that value directly for more accurate zones. The measured value will always be more precise than the 220 minus age estimate.
Official sources
- American College of Sports Medicine (ACSM): acsm.org. ACSM's Guidelines for Exercise Testing and Prescription.
- Karvonen, M.J., Kentala, E., Mustala, O. (1957). The effects of training on heart rate. Annales Medicinae Experimentalis et Biologiae Fenniae, 35(3), 307-315.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology. General information only, not medical advice.