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Heart Rate Zone Calculator

Enter your age (required) and optionally your resting heart rate to get an estimated maximum heart rate (HRmax) and the standard 5-zone training band: Z1 warm-up, Z2 base endurance, Z3 aerobic, Z4 lactate threshold and Z5 VO₂max. The default formula is Tanaka (208 − 0.7 × age), which fits a wider age range than the classic 220 − age. When a resting heart rate is supplied the calculator switches to the Karvonen heart-rate-reserve (HRR) method for a more personalised band.

Max-HR formula

Estimated max heart rate

187 bpm

Method

Karvonen heart-rate reserve (HRR)

Training zones

  • Z1 Warm-up / recovery 50– 60%

    50–60% — easy walking, cool-down, active recovery. Comfortable conversation.

    — bpm

  • Z2 Base endurance 60– 70%

    60–70% — fat-burn, long slow distance, easy jog. Full sentences still possible.

    — bpm

  • Z3 Aerobic 70– 80%

    70–80% — cardiovascular focus, breathing noticeable, only short replies.

    — bpm

  • Z4 Lactate threshold 80– 90%

    80–90% — near anaerobic threshold; only single-word answers.

    — bpm

  • Z5 VO₂max 90– 100%

    90–100% — all-out efforts, sustainable only in short intervals.

    — bpm

Formula

HRmax = 208 − 0.7 × age // Tanaka (recommended) HRmax = 220 − age // Classic Fox/Haskell Target HR (Karvonen) = (HRmax − HRrest) × intensity% + HRrest Target HR (%HRmax) = HRmax × intensity% Z1 50–60% · Z2 60–70% · Z3 70–80% · Z4 80–90% · Z5 90–100%

Frequently asked

Should I use Tanaka or the classic 220 − age?

Default to Tanaka (208 − 0.7 × age). It comes from a 2001 meta-analysis of over 18,000 subjects and has lower average error across the lifespan than the classic equation; both ACSM and the British Heart Foundation now recommend it. The 220 − age formula (Fox & Haskell, 1971) is easier to remember but overestimates HRmax in people under 20 and underestimates it past 60 — sometimes by 10–15 bpm. If you just want a quick gym-style estimate either is fine, but Tanaka is a better default for everyday training plans.

What's the difference between %HRmax and Karvonen / HRR?

The %HRmax method just multiplies your max HR by the intensity (e.g. 60% × 190 = 114 bpm) and ignores resting HR. The Karvonen / heart-rate-reserve method uses HRR = HRmax − HRrest and target HR = HRR × intensity% + HRrest. By including your personal aerobic floor, two people at "70% intensity" with the same HRmax but different RHRs land on different absolute BPM values — Karvonen is generally considered closer to actual perceived effort, especially for well-trained people with low RHR. In this calculator, leave the resting HR field empty for %HRmax or enter it for Karvonen.

Should I stay in Z2 if I want to burn fat?

Z2 (60–70%) is often labelled the "fat-burning zone" because the proportion of energy from fat is highest there. The catch: total calories burned matter more than the percentage from fat. Z3–Z4 burns a smaller share from fat but a much larger total per minute, so an equal-duration Z4 session can outpace Z2 in absolute fat usage. The pragmatic plan most endurance coaches use is "80/20 polarised training": ~80% of weekly volume in easy Z2, ~20% in hard Z4–Z5 intervals, with little time in Z3.

Are estimated heart rate zones actually accurate? Do I need a maximal test?

Population formulas (both Tanaka and 220 − age) have a standard deviation of about ±10–12 bpm. That means your true HRmax could be 10+ BPM off from the estimate, which shifts every zone in lockstep. For casual fitness, recreational running and beginners that's usually fine. For competitive athletes — or anyone using a heart-rate monitor alongside lactate-threshold metrics — a graded exercise test (GXT) at a sports-medicine lab is the gold standard. Lactate-threshold or critical-power testing gives even more individual training zones than HRmax-based ones.

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