Which formula should I use?

For adults under 40, Fox (220-age) is fine. For adults over 40, Tanaka (208 - 0.7×age) is more accurate — it underestimates less. For women specifically, Gulati (206 - 0.88×age) is best, especially for stress-test interpretation. None of the formulas are perfect; an exercise stress test gives the only true MHR.

How accurate are these estimates?

Standard error is roughly 7-12 bpm. So if Fox says your max is 180, your true max could be anywhere from 168 to 192. For training-zone purposes this is usually close enough; for race pacing or VO2max testing, get a graded exercise test.

What are the 5 training zones?

Zone 1 (50-60% MHR): warm-up, recovery · Zone 2 (60-70%): fat-burn, base building · Zone 3 (70-80%): aerobic, cardio · Zone 4 (80-90%): threshold, lactate · Zone 5 (90-100%): peak, VO2 max intervals. Most cardio benefits come from Zone 2-3; lactate/peak training from Zone 4-5.

Should I use heart rate or perceived exertion?

Both. Heart rate is objective but lags 30-60 seconds behind effort and varies with hydration, heat, sleep, caffeine. Rate of Perceived Exertion (RPE 1-10) is subjective but immediate. Best practice: train by RPE, validate with HR.

Why does my watch show different MHR?

Most fitness watches start with the Fox formula and refine over time using your actual peak HR observations. After a few months of hard intervals, your watch's MHR is usually more accurate than any age-based formula.

Max Heart Rate by Age Calculator

Health & Fitness· 18 tools

Free maximum heart rate calculator. Compare three peer-reviewed estimates of MHR — the classic Fox formula (220 − age, ±10–12 bpm error), Tanaka et al. (more accurate for adults over 40), and Gulati (validated specifically for women). Each estimate also generates the five common training zones (50–60 / 60–70 / 70–80 / 80–90 / 90–100% MHR) for endurance, fat-burn, cardio, threshold, and peak training.

Age

Sex

Formula

Recommended for you: FOX

Standard error · ±7–12 bpm. Your true MHR can only be measured by a graded exercise stress test.

Estimated max heart rate

184 bpm

Fox (220 − age)185 bpm

Tanaka (208 − 0.7×age)184 bpm

Gulati (206 − 0.88×age)175 bpm

Training zones (% of 184 bpm)

Zone	% MHR	Heart rate
Z1 Recovery	50–60%	92–110 bpm
Z2 Fat burn	60–70%	110–128 bpm
Z3 Aerobic	70–80%	128–147 bpm
Z4 Threshold	80–90%	147–165 bpm
Z5 Peak	90–100%	165–184 bpm

Disclaimer: For informational purposes only. This is not medical advice — consult a qualified healthcare provider for personal recommendations.

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