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Heart Rate Zone Calculator
Step 1 of 10%
How it works
We use the Tanaka formula (208 − 0.7 × age) which is more accurate than the older 220 − age. If you supply resting HR, we use the Karvonen reserve method which personalises zones to your fitness.
Worked example
Age 35, RHR 60: Max ≈ 184 bpm. Z2 (Karvonen 60–70%) = 134–147 bpm — your easy long-run zone.
Who should use this
- •Runners and cyclists training by HR
- •Beginners using zone-2 'aerobic base' training
- •Anyone returning to exercise wanting safe intensity
Common mistakes
- ×Using 220 − age (overestimates for adults under 40, underestimates for 50+)
- ×Trusting wrist HR for intervals — cadence lock-on is common
- ×Doing every run in Z3 'grey zone' instead of polarising easy/hard
Frequently asked questions
What's the most accurate way to find max HR?▾
A supervised exercise test or repeated all-out 3–5 min efforts after a thorough warm-up.
Why is my HR drifting up at the same pace?▾
Cardiac drift from heat, dehydration or fatigue — slow down or hydrate.
Should beginners do zone 5?▾
Build a base in Z1–Z2 for 8–12 weeks first, then add short Z4–Z5 intervals.