Heart Rate Zone Calculator
More accurate than "220 − age": the Tanaka formula + the Karvonen formula that accounts for individual differences.
Add your resting heart rate and you get far more accurate zones.
5-zone training heart rates Using the Karvonen HRR formula
| Zone | %HRR | HR range (bpm) | Character · purpose |
|---|---|---|---|
| Z1 — Recovery | 50~60% | — | Warm-up · cool-down · recovery days |
| Z2 — Aerobic base | 60~70% | — | Long-slow-distance · fat burning |
| Z3 — Tempo | 70~80% | — | Improves aerobic capacity |
| Z4 — Lactate threshold | 80~90% | — | Race pace · endurance |
| Z5 — VO2max | 90~100% | — | Max oxygen capacity · intervals |
Why "220 − age" is inaccurate, and the formulas that are not
"220 − age" (the Fox formula, 1971) is the one you learned in school, but its error is ±10–20 bpm — quite large. It is based on 1971 average data from American smokers, so it fits modern runners poorly.
Currently recommended formulas
- Tanaka (2001):
HRmax = 208 - 0.7 × age
The most widely accepted formula today. Validated for ages 18–81. - HUNT (2013):
HRmax = 211 - 0.64 × age
For fit adults. Recommended for active runners. - Fox (1971):
HRmax = 220 - age
An old, simple formula. For reference only.
Karvonen formula (1957) — accounts for individual differences
HRR (reserve) = HRmax − resting HRTarget HR = (HRR × intensity%) + resting HR- More accurate than plain %HRmax. The lower your resting heart rate, the lower your absolute heart rate at the same intensity (evidence of improving fitness).
How to measure resting heart rate
- In the morning before getting up, measure your wrist or neck pulse for 1 minute in bed
- A 3-day average is most accurate
- Typical adult 60–80, runner 40–60, elite 30–50 bpm
The most accurate value comes from direct measurement: your heart rate right after an all-out 1 km sprint (following a 5-minute warm-up) is effectively your HRmax. The formulas above are just a starting point.
Your heart rate never lies — only your running partners might
Your Z2 might be someone else's Z4. Run with a friend who is too fast and every easy run turns into intervals. The real answer is a crew of runners at a similar pace.
