Heart rate zones calculator
Estimate maximum heart rate from age (Tanaka 2001: 208 − 0.7×age; Fox 1971: 220 − age; the Gulati 2010 women’s equation; Nes 2013 HUNT) and split the ACSM five training zones (recovery, aerobic, tempo, threshold, VO2max) with the Karvonen heart-rate-reserve formula (1957) or plain %HRmax.
Runs in your browserEvery computation happens in your browser — your data never leaves this device.
Age and resting heart rate
These equations give a population average with up to ±10 bpm individual error — use a measured max heart rate when you have one.
Result
Enter your age, then press “Calculate zones”.
What this tool does
- Build a run or bike plan from five concrete bpm bands instead of vague notions of easy and tempo pace.
- When your watch’s zones look off, recompute them from your age and resting heart rate and enter the numbers manually.
- Train an aerobic base by holding Z2 — for a 40-year-old with a 60 bpm resting rate that is 132–144 bpm, not whatever feels slow.
- Check the Z4/Z5 boundaries before interval work so every rep does not drift into the anaerobic zone and wreck the session quality.
Example
Input
Age 40, resting heart rate 60 bpm, Tanaka (2001), Karvonen %HRR method
Output
Max heart rate 180 bpm, reserve 120 bpm; Z1 120–132, Z2 132–144, Z3 144–156, Z4 156–168, Z5 168–180 bpm
Tanaka gives 208 − 0.7 × 40 = 180 bpm at 40, coincidentally the same as Fox’s 220 − 40; away from that age the two equations diverge noticeably.
Frequently asked questions
Why is 220 − age considered inaccurate?
Its standard deviation is about ±10–12 bpm, so it can miss your true maximum by more than ten beats. Tanaka et al. (2001) regressed 351 studies into 208 − 0.7×age, which fits better and is the default here. A measured max from a hard 5 km or a ramp test is still the gold standard.
How do Karvonen and %HRmax differ?
Karvonen works from heart rate reserve (max − resting), so people with a low resting rate get wider, more realistic bands. %HRmax just scales the maximum and ignores individual resting rate. The tool computes both — switch the method to compare.
Is there really a “fat burning zone”?
Fat contributes the largest share of fuel at low intensity, but total calorie burn is also lowest. Fat loss is driven by the energy deficit, not the zone. Z2 earns its place because you can hold it for a long time and recover quickly.
How should I measure resting heart rate?
Take it right after waking, before getting up, counting for a full 60 seconds, and average over several days. Poor sleep, caffeine and illness all push it up, so a single reading is not reliable.
Do these zones suit everyone?
Anyone on beta blockers or other rate-controlling medication, or with an arrhythmia, should not trust formula-based or even measured zones. Use perceived exertion (RPE) instead and talk to a clinician.
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