Heart Rate Zones Calculator
Heart rate training breaks effort into 5 zones — recovery, endurance, tempo, threshold, max. The right zone depends on your goal (zone 2 for endurance base, zone 4 for race pace, zone 5 for VO2max intervals). Two issues to settle first: which max-HR formula (220−age is famous but inaccurate; Tanaka 208−0.7×age is better for adults; Gulati for women), and which percentage method (%MHR is simpler; %HRR / Karvonen accounts for your resting HR and is more individualized).
Max HR
187 bpm
- Z1
Recovery
Active recovery, very light
124–136
50–60%
- Z2
Endurance
Aerobic base, all-day pace
136–149
60–70%
- Z3
Tempo
Marathon pace, conversational hard
149–162
70–80%
- Z4
Threshold
Lactate threshold, sustainable for ~1h
162–174
80–90%
- Z5
Max / VO2
VO2max intervals, max effort
174–187
90–100%
Formulas are estimates — actual max HR can vary ±10-15 bpm. A field test (e.g. 20-min all-out) gives a more accurate personal number.
How to use
- Enter your age. If you know your resting HR (best taken first thing in the morning), enter it.
- Pick a max-HR formula. Tanaka is the most accurate for general adults.
- Pick %MHR (simpler) or %HRR (more accurate). Use the zone bands to target your workout.
Frequently asked questions
- Why not just use 220−age?
- It's from a 1971 study with a small sample. Real population variation is wide — Tanaka (208−0.7×age, n=18,712) is more accurate for adults. Gulati (206−0.88×age) is from women-specific data.
- %MHR vs %HRR — what's the difference?
- %MHR is 'X% of max heart rate'. %HRR (Heart Rate Reserve, aka Karvonen) is 'X% of the range between resting and max'. HRR accounts for fitness level — fitter people have lower resting HR, so HRR gives them slightly higher absolute bpm targets.
- Why does zone 2 feel so easy?
- It is. Zone 2 is conversational effort. Most elite endurance athletes do 60-80% of training there because aerobic adaptations happen at that intensity without the recovery cost of harder work.
- Are these zones for me if I'm on beta blockers?
- No — beta blockers significantly lower max HR. The formulas don't account for this. Use RPE (perceived exertion) or get a doctor-prescribed target range instead.
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