ZovaTool

Target Heart Rate Calculator

Max HR (Tanaka)
187 bpm
Max HR (Fox 220−age)
190 bpm
Max HR (Tanaka M)
186 bpm
Heart Rate Reserve
122 bpm
Karvonen method
Training Zones (Karvonen: %HRR + RHR)
Zone 1 — Recovery126–138 bpm
%HRmax: 94–112 bpm
Zone 2 — Fat burn / Endurance138–150 bpm
%HRmax: 112–131 bpm
Zone 3 — Aerobic150–163 bpm
%HRmax: 131–150 bpm
Zone 4 — Anaerobic / Threshold163–175 bpm
%HRmax: 150–168 bpm
Zone 5 — Max / VO₂175–187 bpm
%HRmax: 168–187 bpm
Formulas
Fox: HRmax = 220 − age
Tanaka: HRmax = 208 − 0.7 × age
Gulati (women): HRmax = 206 − 0.88 × age
Karvonen: Target = (HRmax − RHR) × intensity% + RHR

How to use the Target Heart Rate Calculator

  1. Enter age and resting heart rate (measured first thing in the morning).
  2. Pick sex (uses Gulati formula for women).
  3. Read the 5 Karvonen training zones from recovery to VO₂ max.
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Training zones: where the work happens

Tanaka (208 − 0.7×age) is more accurate than the classic 220−age for most adults. Gulati (206 − 0.88×age) fits women better.

Karvonen's method uses heart rate reserve (HRmax − RHR), which scales zones to your fitness, not just age. A lower resting HR widens the higher zones.

Zone 2 is the "fat burning" zone where mitochondrial adaptations are strongest. Zone 4–5 work builds VO₂ max but should be a small fraction of weekly volume.