Sports Calculators
Heart Rate Zones Calculator
Find your target heart rate zones for training.
Enter the values and review the result.
Used to estimate max heart rate as 220 - age.
Measure this when you first wake up. Required for the Karvonen heart-rate-reserve method.
Calculation assumptions
- *Zones are estimated with the Karvonen heart-rate-reserve method.
- *Heart-rate response varies by fitness level, medication, heat, stress, sleep, hydration, and training history.
- *Results are estimates, not medical or coaching advice.
Enter your values and press Calculate.
Results and breakdowns will appear here after a valid calculation.
How Heart Rate Zones are Estimated
This calculator uses the Karvonen method: target heart rate = resting heart rate + intensity x (estimated max heart rate - resting heart rate). Estimated max heart rate is 220 - age.
Example: age 30 and resting heart rate 60 gives an estimated max of 190 BPM and a heart-rate reserve of 130 BPM. Zone 2 at 60-70% HRR is about 138-151 BPM.
Safety notes and common mistakes
Heart-rate zones are training estimates. Lab testing, wearable devices, medication, heat, fatigue, stress, sleep, and health status can all change your real training response.
- Do not treat zones as a medical diagnosis or treatment plan.
- Measure resting heart rate consistently, ideally after waking.
- Do not ignore chest pain, dizziness, unusual shortness of breath, or fainting.
- Use professional guidance before intense exercise if you have heart conditions, medication use, pregnancy, or medical concerns.
Transparency note
Accuracy and limitations
Calzivo tools are built for practical estimates, conversions, and checks. Some tools use standard formulas or simplified assumptions, and results can be affected by input accuracy, rounding, units, local rules, or changing official requirements.
Results depend on the values you enter and any simplified assumptions used by the tool. Verify important results before making decisions or submitting official information.
How to Use This Tool
Use these steps to enter the right inputs and interpret the result correctly.
Enter your current age.
Enter your resting heart rate (BPM).
The tool calculates zones using the Karvonen heart-rate-reserve formula, which uses resting heart rate.
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Related Guides
Background reading and explanations related to Heart Rate Zones Calculator.
Frequently Asked Questions
Common questions about Heart Rate Zones Calculator and how to read the result.
What is the Karvonen formula?
It's a mathematical formula that helps determine your target heart rate training zone by taking into account both your maximum and resting heart rates.
Are heart-rate zones exact?
No. They are estimates and can differ from lab-tested zones or device-based recommendations.
What is heart-rate reserve?
Heart-rate reserve is estimated max heart rate minus resting heart rate. Karvonen zones apply intensity percentages to that reserve.
Why does resting heart rate matter?
Resting heart rate personalizes the zone estimate more than using only a simple percentage of max heart rate.
Can medication affect heart-rate zones?
Yes. Some medications and health conditions can change heart-rate response. Use professional guidance if this applies to you.
Is this medical advice?
No. It is a training estimate and should not be used to diagnose, treat, prevent, or manage a medical condition.