Heart rate zones calculator
Enter your age or your measured HRmax: the calculator gives your five training zones in beats per minute, as a percentage of HRmax and, if you know your resting heart rate, with the Karvonen method.
About 20 seconds
The formulas used
Zone as % of HRmax = HRmax × the zone percentage
Karvonen zone = resting HR + (HRmax − resting HR) × the zone percentage
With no measured HRmax, it is estimated with the Tanaka formula: 208 − 0.7 × age.
For an HRmax of 180 bpm, zone 2 (60–70% of HRmax) runs from 108 to 126 bpm. With a resting heart rate of 60 bpm, the Karvonen method puts it between 132 and 144 bpm.
Heart rate reserve method: Karvonen, Kentala & Mustala, Annales Medicinae Experimentalis et Biologiae Fenniae, 1957. HRmax estimate: Tanaka, Monahan & Seals, Journal of the American College of Cardiology, 2001. Five-zone split: intensity classification of the American College of Sports Medicine.
The five zones and what they are for
| Zone | % HRmax | What it is for |
|---|---|---|
| Z1 — Recovery | 50–60% | Warm-up, cool-down and recovery sessions between two hard blocks. |
| Z2 — Base endurance | 60–70% | The aerobic foundation: you can still hold a conversation, high volume, heavy use of fat as fuel. |
| Z3 — Tempo | 70–80% | Sustained but repeatable: builds efficiency and aerobic capacity. |
| Z4 — Threshold | 80–90% | Around the lactate threshold: raises the pace you can hold before lactate piles up. |
| Z5 — VO2max | 90–100% | Short, intense intervals: develops maximal aerobic power. |
% of HRmax or Karvonen?
The percentage of HRmax needs one value only and is enough for most sessions: it is what watches and chest straps apply by default.
The Karvonen method works from the heart rate reserve, the gap between your resting and maximum heart rates. It makes the zones personal: at the same HRmax, a runner resting at 45 bpm and a beginner resting at 75 bpm do not get the same ranges.
In practice, pick one method and stay with it: the two do not give the same bpm for the same percentage, and switching blurs any comparison from one training block to the next.
How to use your zones
Split the volume rather than the intensity: roughly 80% of training time in zones 1 and 2 and the rest in zones 4 and 5 is the best documented pattern among endurance athletes.
Heart rate lags behind effort and drifts upwards with heat, fatigue or dehydration: on very short efforts, trust pace or power rather than bpm.
Recalculate your zones after an HRmax test, or as soon as your resting heart rate has shifted by a few beats for good.
Work out my maximum heart rate · Estimate my VO2max with the Cooper test · See all calculators
Frequently asked questions
A few common questions about heart rate training zones.
Multiply your HRmax by the bounds of each zone: 50–60% for zone 1, 60–70% for zone 2, 70–80% for zone 3, 80–90% for zone 4 and 90–100% for zone 5. With an HRmax of 180 bpm, zone 2 runs from 108 to 126 bpm.
It builds the zones from the heart rate reserve: resting HR + (HRmax − resting HR) × the percentage. Published in 1957, it accounts for your resting heart rate and therefore returns higher ranges than a plain percentage of HRmax.
It is the base endurance zone, between 60 and 70% of HRmax — a pace at which you can still hold a conversation. It carries most of the volume for endurance athletes because it builds the aerobic base at a low recovery cost.
It helps. An HRmax estimated from a formula carries a margin of 10 to 12 bpm, and that margin lands directly on every zone boundary. If you have a value from a field test or a lab test, enter it.
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