Heart Rate Zones Calculator
Five zones from max heart rate. Enter a measured max if you have one; otherwise the age formula is used.
Max heart rate
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Z1 recovery 50–60%
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Z2 aerobic 60–70%
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Z3 tempo 70–80%
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Z4 threshold 80–90%
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Z5 max 90–100%
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Worked example
At 30, the Tanaka formula gives a max of 187 bpm — six beats lower than the classic 220 minus age. Zone 2 then runs from 112 to 131.
Zone training assigns effort levels to heart rate bands so that easy days stay easy and hard days stay hard. The failure mode is doing everything in zone 3, which is too hard to recover from and too easy to drive adaptation.
Which max heart rate formula
220 minus age overestimates for younger people and underestimates for older ones. Tanaka (208 − 0.7 × age) fits measured data better and is used here. Neither substitutes for an actual test.