Free Tool
Target Heart Rate Calculator
Enter your age. We compare every major HRmax formula and map your 5 training zones. Add resting HR and we switch to Karvonen heart-rate reserve for more accurate zones.
New to Zone 2 cardio? Read the plain-English definition →
About you
Max heart rate across formulas
Recommended formula for your profile is highlighted.
| Method | HRmax |
|---|---|
Fox (220 - age) Fox, Naughton, Haskell (1971) | 190 bpm |
Tanaka (208 - 0.7 × age)Best fit Tanaka et al. (2001), JACC 37(1):153 | 187 bpm |
Your 5 training zones
Computed as percentages of HRmax. Add resting HR above for Karvonen zones.
Recovery
Active recovery, easy warmups, walking. Conversational.
Aerobic base
Fat oxidation, mitochondrial development, long slow distance.
Aerobic / tempo
Comfortably hard. Builds aerobic capacity. Talk in short sentences.
Threshold
Lactate threshold. Sustainable for about 20-60 minutes when trained.
VO2 max / anaerobic
All-out intervals. Builds VO2 max and anaerobic power.
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Connect your watch and Zealova vibrates when you drift out of your target zone.
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Methodology + Sources
- Fox SM, Naughton JP, Haskell WL (1971). Physical activity and the prevention of coronary heart disease. Annals of Clinical Research 3(6):404-432.
- Tanaka H, Monahan KD, Seals DR (2001). Age-predicted maximal heart rate revisited. Journal of the American College of Cardiology 37(1):153-156.
- Gulati M, Shaw LJ, Thisted RA, Black HR, Bairey Merz CN, Arnsdorf MF (2010). Heart rate response to exercise stress testing in asymptomatic women. Circulation 122(2):130-137.
- Karvonen MJ, Kentala E, Mustala O (1957). The effects of training on heart rate. Annales Medicinae Experimentalis et Biologiae Fenniae 35(3):307-315.
Last updated: 2026-05-14
Built by Sai, founder of Zealova. Not a neutral third party. Calculator results are estimates. For medical decisions, consult a qualified professional.
Frequently asked questions
Which HRmax formula is most accurate?+
Tanaka (208 - 0.7 × age) outperforms the classic 220 - age rule across nearly every age group. For women under 40, Gulati (206 - 0.88 × age) is even tighter. The original Fox formula is fine as a rough rule of thumb but has an error margin of ±10-12 bpm. Lab-measured HRmax is still the gold standard for serious athletes.
Why does Karvonen need resting HR?+
Karvonen calculates zones from heart rate reserve (HRmax minus resting HR), which scales each zone to your individual cardiovascular fitness. A 30-year-old with a resting HR of 50 lands in zone 2 at very different absolute bpm than a 30-year-old with a resting HR of 75. Without resting HR, we have to fall back on simple percentages of HRmax.
What zone burns fat?+
Zone 2 (60-70% of HRmax) maximizes the percentage of fuel coming from fat. But total calories burned matters far more than fuel mix for body composition. A hard zone 4 session burns more total calories and more fat in absolute terms than an easy zone 2 session of the same duration. Use zone 2 for aerobic base, not for "fat burning" in isolation.
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