Heart Rate Zones Calculator

Your 5 training zones

Endurance training is most often divided into five zones based on percentage of max heart rate. Lower zones build aerobic base and recovery; upper zones build threshold and VO2max.

Zone	Label	% Max HR	BPM range	What it builds
Z1	Recovery	50 — 60 %	—	Active recovery, very long efforts
Z2	Easy / endurance	60 — 70 %	—	Aerobic base, fat oxidation
Z3	Aerobic	70 — 80 %	—	Tempo, sustainable hard work
Z4	Threshold	80 — 90 %	—	Lactate threshold, race pace
Z5	VO2max	90 — 100 %	—	VO2max intervals, top-end speed

What is heart-rate-zone training?

Heart-rate-zone training is a way to anchor cardio intensity to your physiology rather than to pace or perceived effort. Each zone — typically five of them — corresponds to a percentage of your maximum heart rate (or, with Karvonen, of your heart-rate reserve), and each one trains a different system: very easy work for recovery and aerobic base, harder work for tempo and lactate threshold, and short hard intervals for VO2max. Endurance coaches across running, cycling, rowing and triathlon use the 5-zone model because it makes "easy days easy and hard days hard" — the polarized 80/20 distribution that consistently outperforms moderate-intensity-everywhere training in research. Two practical notes: maximum heart rate is highly individual. Formula-based estimates (Tanaka or 220-age) are accurate to about ±10-12 bpm one standard deviation, so two people the same age can differ by 15+ bpm. If you have a reliable lab or field-test max HR, use that instead. Resting HR matters too. Karvonen's method incorporates it via heart-rate reserve, which usually gives more individualized zones, especially for people with low or unusually high resting heart rates. Training zones aren't a diagnostic tool — they're a guide for distributing effort over a week.

How to use this calculator

1. Enter your age. 2. Optionally add your resting HR — measure it for 30 seconds first thing in the morning before getting out of bed. 3. Pick a method: Tanaka (208 − 0.7 × age) is more accurate above 40 than the classic 220 − age. Karvonen uses heart-rate reserve and needs your resting HR. The five zones populate automatically with BPM ranges, which you can copy into a watch or app.

The three methods

Tanaka: Max HR = 208 − 0.7 × age Classic: Max HR = 220 − age Karvonen: Zone HR = RHR + intensity% × (Max HR − RHR) where intensity% are the zone bounds (50, 60, 70, 80, 90, 100). The Tanaka formula is more accurate for adults over 40; the classic 220-age tends to overestimate young max HR and underestimate older max HR. Karvonen's heart-rate reserve typically nudges easy zones up and hard zones down compared to a flat % Max HR, giving more personalized targets.

Tips for finding your real max HR

Formula-based max HR is a starting point. To find your real number: warm up well, then run a hard 4 km uphill, sprint the last 500 m all-out, and record the peak HR — that's a close field estimate. A graded VO2max test in a lab is the gold standard. Update the calculator whenever you have a more reliable number.

Frequently asked questions

Why does Tanaka give a different max HR than 220-age?

The classic 220-age came from a 1970s graph fit, not a study. Tanaka et al. (2001) re-derived it from a meta-analysis of ~19,000 people and got 208 − 0.7 × age. For people over 40, Tanaka is consistently closer to lab-measured max HR — it adds 5-10 bpm at age 50.

Should I use plain % Max HR or Karvonen?

Karvonen (heart-rate reserve) tends to be more personalized because it uses both the ceiling (max HR) and the floor (resting HR). If you have a reliable resting HR — measured in the morning before getting up — Karvonen is usually better. If you don't, plain % Max HR is fine.

How do I measure my resting heart rate?

Measure first thing after waking, lying still, before any caffeine. Use a wearable for a 5-minute average, or count pulse beats for 30 seconds and double. Take it for 5-7 mornings and use the median; it shifts with sleep, illness and training load.

What if my heart rate doesn't match the zones?

Heart rate is influenced by sleep, hydration, heat, caffeine, recent meals, and training stress. If your easy run feels easy but the watch says Z3, check those factors before changing zones. Cardiac drift in long efforts also pushes HR up at constant pace.

Can I use these zones on a bike or rower?

Yes, but max HR varies by sport — typically cycling max HR is 5-10 bpm lower than running max HR for the same person, and rowing falls between. Ideally, test or measure max HR per sport and use sport-specific zones.

Are these zones safe if I have heart issues?

Formula-based zones aren't a substitute for medical clearance. If you have known cardiac disease, hypertension, take HR-lowering drugs (e.g. beta-blockers), or are over 40 and starting hard cardio, get cleared by a doctor and use clinical-grade testing instead.

Heart Rate Zones Calculator