For educational and tracking purposes only. Results are estimates and are not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional.
Calculator tool
How this calculator works
Use the explanation to understand the formula, assumptions, and practical limits behind the calculator result.
What the Calculator Uses
The calculator first estimates maximum heart rate as:
It then applies the selected intensity to heart-rate reserve using the Karvonen formula:
Why Two Zones Appear
The result panel shows:
- A basic zone using a percentage of estimated max heart rate
- A Karvonen zone that also uses resting heart rate
The Karvonen method adapts more to the individual resting-heart-rate input, but both are still estimates.
Intensity Bands
| Selected intensity | Range used |
|---|---|
| Light | 50-60% |
| Moderate | 60-70% |
| Vigorous | 70-85% |
| Maximum | 85-100% |
Important Limits
Age formulas are averages. Fitness level, medication, heart rhythm issues, illness, and clinician instructions can make a personal target very different from the estimate.
Frequently asked questions
Why does resting heart rate change the Karvonen result?
Karvonen uses heart-rate reserve, which is the gap between estimated maximum and resting heart rate. Two people of the same age can therefore get different target zones if their resting heart rates differ.
Is 220 minus age exact?
No. It is a simple population estimate. Individual maximum heart rate can differ substantially, so the number is best used as a starting point rather than a precise physiological limit.
Can medication affect the result?
Yes. Some medicines, especially those that change heart-rate response, can make standard exercise zones less useful. Follow clinician guidance when medication or heart disease is involved.
Which zone should a beginner use?
Beginners often start with lower-to-moderate intensity and build gradually, but the right target depends on health status, symptoms, and professional advice. The calculator shows ranges; it does not clear someone for exercise.
