Zone 1
Move easily
50–60% of HRmax
94–112 beats/min
Very light effort. Conversation is effortless. Suitable for easy movement, warming up and cooling down.
Knowledge & Tools · Exercise
Calculate heart rate zones with optional resting HR
Your heart rate zone calculator: enter your age and optionally your resting heart rate and a reliably measured maximum heart rate to explore four estimated training ranges.
Your details
Your guide
Estimated maximum heart rate
Tanaka formula: 208 − 0.7 × age
187 beats/min
This calculator uses four bands of 10 percentage points of maximum HR or heart rate reserve, depending on the method. Other training models may use different boundaries.
Method: percentage of maximum heart rate
Zone 2
Build your aerobic base
60–70% of HRmax
112–131 beats/min
Light, steady effort. You can still speak comfortably in full sentences. A guide for longer, easy endurance sessions.
Zone 3
Pick up the pace
70–80% of HRmax
131–150 beats/min
Noticeably harder effort, with faster breathing. Conversation becomes more difficult. For brisk endurance sessions with recovery afterwards.
Zone 4
Train at high intensity
80–90% of HRmax
150–168 beats/min
High effort; only a few words at a time are possible. Best suited to short intense efforts with appropriate training experience. Allow time for recovery.
Combine heart rate with how you feel
“Zone 2” is not defined identically in every model. The calculated 60–70% is a rough guide and does not identify your individual metabolic or lactate threshold. During easy training, you should still be able to speak in full sentences. Heat, stress, medication and training status can affect heart rate.
Below 50%, effort falls below the ranges shown here. Above 90%, effort is very high and is not a general training target of this calculator.
How accurate are the results?
All zones remain estimates and guidance. Karvonen accounts for resting heart rate but is not automatically more accurate. Equal percentages of maximum heart rate and heart rate reserve are not equivalent.
Smartwatches may offer more personalized estimates using individual data, but are not inherently more accurate. Sensor errors, different formulas and zone models can explain differences. Measuring your pulse alone does not measure your aerobic or anaerobic threshold.
Even a reliably measured maximum heart rate does not determine individual thresholds. Professionally interpreted lactate testing or cardiopulmonary exercise testing is better suited to this. Aerobic and anaerobic energy production overlap; zone boundaries are not switches.
How to interpret these numbers
Your actual maximum heart rate may differ considerably from this estimate. An age-based formula does not replace an individual exercise assessment. Rounded boundaries are approximations, not sharp transitions.
If you are new to exercise, start with light effort and progress gradually. If you have cardiovascular disease or take medication that affects heart rate, have a clinician determine your training ranges. Stop exercising and seek medical assessment if you experience chest pain, dizziness or unusual shortness of breath.
Further reading
- Tanaka et al. (2001): Age-predicted maximum heart rate
- HERITAGE study: Limitations of individual predictions
- American Heart Association: Target heart rates and exercise intensity
The four 10-percentage-point bands are this tool’s simplified model. The AHA describes moderate effort as approximately 50–70% and vigorous effort as approximately 70–85% of maximum heart rate.
More about exercise and longevity →Questions and answers
When does this calculator use Karvonen?
With resting HR, the tool calculates ranges from heart rate reserve: resting HR plus intensity times the difference between maximum and resting HR. Without resting HR, it uses percentages of maximum HR.
Why does my smartwatch show different zones?
Watches may use different zone models, a different maximum HR or individual estimates. These calculator ranges are not measured aerobic or anaerobic thresholds.