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Heart Rate Zone Calculator
Training zones, using a formula that is not 220 minus age.
What it does. Training zones are percentages of your maximum heart rate, or better, of your heart rate reserve — the gap between resting and maximum. Every age-based formula is a population average with a standard deviation of 10 to 12 beats, so treat the zones as guidance rather than boundaries.
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How to use Heart Rate Zone Calculator
- Enter your age, and your resting heart rate if you know it.
- Choose a formula and zone model.
- Read the beats-per-minute range for each zone.
Why not 220 minus age
The 220-minus-age rule has no research pedigree — it was an informal fit noted in the 1970s and repeated until it became doctrine. It systematically overestimates maximum heart rate in younger people and underestimates it in older people.
Tanaka's formula, 208 minus 0.7 times age, was derived from a large meta-analysis and predicts better across the age range.
Both still carry a standard deviation of around 10 to 12 beats per minute. That means a formula-derived maximum can be 20 beats off for a completely normal person, which is more than the width of a zone.
Percentage of maximum, or of reserve
The simple method takes percentages straight off maximum heart rate. The Karvonen method uses heart rate reserve — maximum minus resting — and adds resting back in.
Karvonen accounts for fitness: a well-trained person with a resting rate of 45 gets different zones from someone at 75, which the simple method cannot see.
Karvonen needs a genuine resting heart rate — measured on waking, before getting up. A daytime seated reading is typically 10 to 15 beats high and will skew every zone.
The five zones
| Zone | % of max | Feels like | Purpose |
|---|---|---|---|
| 1 Recovery | 50–60% | Very easy, full conversation | Active recovery |
| 2 Aerobic | 60–70% | Easy, can talk in sentences | Aerobic base, fat oxidation |
| 3 Tempo | 70–80% | Comfortably hard, short sentences | Aerobic capacity |
| 4 Threshold | 80–90% | Hard, a few words | Lactate threshold |
| 5 Maximum | 90–100% | All out, no talking | Anaerobic power |
The talk test is the useful cross-check. If your monitor says zone 2 and you cannot speak a sentence, believe your lungs — your formula-derived maximum is probably wrong.
Frequently asked questions
Is 220 minus age accurate?
No. It was an informal fit from the 1970s with no research pedigree, and it overestimates maximum heart rate in younger people while underestimating it in older ones. Tanaka — 208 minus 0.7 times age — predicts better.
What is the Karvonen method?
It calculates zones from heart rate reserve — maximum minus resting — then adds resting back. It accounts for fitness, so a trained person with a low resting rate gets appropriately different zones.
How do I measure resting heart rate?
On waking, before getting up, ideally averaged over several mornings. A daytime seated reading typically runs 10 to 15 beats high and will skew every zone.
How far off can a formula be?
Age-based formulas carry a standard deviation of 10 to 12 beats per minute, so being 20 beats out is entirely normal. That is wider than a zone, which is why the talk test is a useful cross-check.
Should I train by heart rate or by feel?
Both, and trust feel when they disagree. Heart rate lags effort, drifts upward in heat and with dehydration, and is built on an estimated maximum — while your own perceived effort has none of those problems.