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Heart Rate Zone Calculator: Training Zones

Find your max heart rate and five personalized training zones using the Karvonen method, so you train at the right intensity for your goal.

Your max heart rate

187 bpmHR reserve: 127 bpm (Karvonen)
HRmax
187 bpm
Resting
60 bpm
Reserve
127 bpm
Method
Tanaka
ZoneLabelbpm
Z1Recovery124-136
Z2Easy / fat burn136-149
Z3Aerobic149-162
Z4Threshold162-174
Z5Max174-187

How heart rate zones are calculated

This calculator uses the Karvonen method, which is more personalized than simple percent-of-max. Karvonen works from your heart rate reserve, the difference between your max heart rate and your resting heart rate, and adds a percentage of that reserve back to your resting rate.

  • HRmax = 208 − 0.7 × age (Tanaka)
  • HRR = HRmax − HRrest
  • Zone target = HRR × intensity + HRrest

Karvonen makes a meaningful difference for fit people with low resting HR. A 30-year-old with a resting HR of 50 has a much wider usable range than the same person at 75.

What each zone is for

  • Z1, recovery (50-60%): Warm-up, cool-down, walking after a hard session.
  • Z2, easy / fat burn (60-70%): Conversation pace. Long aerobic base work belongs here, this is where most weekly volume should sit.
  • Z3, aerobic (70-80%): Steady cardio, tempo. Useful but easy to overuse; many runners live here and never improve.
  • Z4, threshold (80-90%): Hard but sustainable for 20-60 minutes. Lactate threshold work, cruise intervals.
  • Z5, max (90-100%): Short max-effort intervals, 30s to 5 min. VO₂ max territory.

How to use zones

The classic polarized approach is roughly 80% of training time in Z1-Z2 and 20% in Z4-Z5, with very little in Z3. This sounds backwards if you've been pushing every run, but elite endurance athletes have trained this way for decades. The slow stuff builds the engine, the hard stuff sharpens it.

Worked example

A 35-year-old with a resting HR of 55 bpm. Tanaka HRmax = 208 − 0.7 × 35 = 184. HRR = 184 − 55 = 129. Z2 (60-70%): 132-145 bpm. Z4 (80-90%): 158-171 bpm. That's a meaningfully different Z2 target than 60-70% of HRmax alone (110-129), which would be too easy.

Common mistakes

  • Training too hard, too often. Most amateurs spend 80% of training in grey-zone Z3 and wonder why they plateau.
  • Trusting wrist HR for intervals. Optical sensors lag and drift. Use a chest strap for hard work.
  • Treating formulas as exact. Tanaka and Fox both have ±10-15 bpm individual variance. If you've measured a true max, use it.
  • Ignoring resting HR changes. A 10 bpm rise in resting HR is a clear overtraining or illness signal.
  • Using HR for strength work. Heart rate during lifting reflects effort and rest, not stimulus. Use RPE and sets/reps instead.

FAQ

Which max heart rate formula is best?+

Tanaka (208 − 0.7 × age) is more accurate across adult age ranges than the older 220 − age. We use Tanaka by default and offer 220 − age for comparison.

What's the Karvonen method?+

It calculates zones from your heart rate reserve (HRmax minus resting HR), not just from HRmax. This personalizes zones based on your fitness, fitter people have lower resting heart rates and therefore more usable range.

Which zone should I train in?+

Most endurance volume should be in Z2 (easy, conversation pace). Add 1-2 weekly sessions in Z4 (threshold) or short Z5 (intervals). Z1 is recovery, Z3 is grey-zone, often overused.

How do I find my resting heart rate?+

Measure first thing in the morning before getting out of bed for 3 consecutive days and average. Typical adult range is 50-80 bpm; trained endurance athletes are often 40-55.

Why is my HR higher than the calculated max?+

These formulas have ±10-15 bpm individual variance. If you've hit a higher HR during all-out efforts and it was reproducible, use that as your true max.

Should I use a chest strap or watch?+

Chest straps are more accurate, especially for intervals. Wrist-based optical HR drifts during high-intensity work and weight training. For zone training, accuracy matters.

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