About this calculator
A heart rate zone calculator estimates training zones from age and optional resting HR using common formulas (Fox, Tanaka, Karvonen).
Who should use it: Endurance trainees structuring easy/hard efforts.
When to use it: Use it to set zone targets after choosing a max-HR method that fits your data.
Heart-rate training zones
Zones 1–5 use 50–60%, 60–70%, 70–80%, 80–90%, and 90–100% of max HR (percent-max methods) or of heart-rate reserve (Karvonen). Enter a measured max HR when you have one.
Step-by-step
Enter age and resting HR
Resting HR is required for Karvonen personalization.
Choose a method
Fox, Tanaka, or Karvonen; optionally override max HR.
Review zones 1–5
Use the bpm bands to structure easy, steady, and hard work.
Worked example: Age 30 Fox zones
Age 30, resting HR 60, Fox method, no max override.
- HRmax = 220 − 30 = 190
- Zone 1 = 50–60% of 190 → 95–114 bpm
- Zone 2 = 60–70% → 114–133 bpm
Max HR 190 bpm with five training bands for easy through maximal effort.
How to interpret the result
Zones are estimates. Perceived effort and lactate/field tests refine them better than age alone.
Key definitions
- HRmax
- Estimated or measured maximum heart rate.
- Heart-rate reserve
- HRmax − resting HR — used by the Karvonen method.
- Zone 2
- Aerobic endurance band often used for base / fat-oxidation training.
Common use cases
- Cardio intensity control
- Zone 2 base building
- Interval upper limits
Tips
- Prefer a field-tested or lab max HR over age formulas when available.
- Most weekly volume should stay in easier zones; reserve Zone 4–5 for quality sessions.
- Medications and illness can change heart-rate response — interpret cautiously.
Common mistakes
Treating age formulas as exact
Fix: Use them as estimates; adjust from perceived effort and test data.
Living in Zone 3 every day
Fix: Keep easy days easy so hard days can be hard.
Limitations
- Medications and conditions affect heart rate response — seek clinical guidance when relevant.
- Not a diagnostic ECG or medical device.