Running / 003
Heart rate zone calculator
Five training zones from your age and pulse — Karvonen when you give a resting rate, percentage of max when you don't, and the page says which it used.
Read the guide: every zone by age from 20 to 70, plus Karvonen zones by resting pulse
Estimated maximum heart rate
KarvonenYour five zones
Zone 2 aerobic base| Zone | % range | Heart rate | For |
|---|
Next / Pace and capacity
Put the zones
to work.
Where the maximum comes from
Every zone on this page is a percentage of something, and that something is your maximum heart rate. Get the maximum wrong and all five zones shift by the same proportion, which is why a measured figure beats an estimated one whenever you have a trustworthy measurement to hand.
Tanaka: max heart rate = 208 − 0.7 × age. A 40-year-old gets 208 − 28 = 180 bpm. It comes from a pooled analysis of a large number of studies and holds up better than the older formula across the age range.
Fox: max heart rate = 220 − age. The same 40-year-old gets 180 bpm, which is a coincidence of that particular age — the two formulas agree near 40 and diverge in both directions from there. A 25-year-old gets 195 from Fox and 190.5 from Tanaka; a 65-year-old gets 155 from Fox and 162.5 from Tanaka.
Both are population averages fitted to groups, not predictions about you. Measured maxima scatter widely around either line, by more than ten beats per minute in many people, which is enough to move a zone boundary by several beats. The result is rounded to the nearest whole beat before the zones are worked out.
Karvonen versus percentage of max
If you enter a resting heart rate, this page uses the Karvonen method: target = (max heart rate − resting heart rate) × percentage + resting heart rate. The bracket is your heart rate reserve, the usable range between sitting still and going flat out, and the percentage is taken from that range rather than from the maximum itself.
If you leave resting blank, the zones are a plain percentage of maximum: target = max heart rate × percentage. Same five bands, different arithmetic, and the two disagree by a wide margin at the easy end. A 40-year-old with a maximum of 180 and a resting rate of 60 gets a Zone 2 of 132 to 144 by Karvonen, against 108 to 126 by percentage of max — a gap of well over twenty beats at the bottom of the range.
Neither is more correct in the abstract. Karvonen is the more common choice for prescribing training because it scales with the individual's resting rate, and it is what this page will use whenever you give it the input it needs. The badge next to the result always names the method actually applied.
What the five zones are for
The boundaries are the conventional ten-percent splits: Zone 1 from 50 to 60 percent, Zone 2 from 60 to 70, Zone 3 from 70 to 80, Zone 4 from 80 to 90, and Zone 5 from 90 to 100. They are a scheme for organizing effort, not measurements of your own physiology — your actual lactate threshold and aerobic threshold sit wherever they sit, and only a lab test or a well-run field test will tell you where.
Zone 2 is banded on the table because it is where most endurance volume belongs and the zone most often skipped past too quickly. It should feel conversational and slightly too easy. The discipline of staying in it is what builds the aerobic base that the harder zones draw on.
Everything on this page is arithmetic on the numbers you type. It cannot see your health history or your prescriptions — beta blockers in particular lower both resting and maximum heart rate, which makes every zone here wrong — and it cannot judge whether hard exercise suits you today. None of it is medical advice. Check with a doctor before any all-out effort or a jump in training load, and especially with a cardiac condition, any drug that alters heart rate, or a recent illness.
Common questions
Which maximum heart rate formula should I use?
Tanaka, 208 minus 0.7 times age, is the default here because it was derived from a much larger pooled analysis and tracks measured maxima better across the age range, particularly over 40. The older 220 minus age is still widely quoted and is offered as an option, but it tends to overestimate younger adults and underestimate older ones. Both are population averages: an individual can sit more than ten beats either side of whichever number you pick.
What is the difference between Karvonen and percentage of max?
Percentage of max takes a flat percentage of your maximum heart rate. Karvonen works from heart rate reserve, the gap between resting and maximum, then adds your resting rate back on. Because it accounts for where your heart actually starts, Karvonen gives higher zone boundaries than the same percentage of max, and the fitter you are the bigger the gap. This page uses Karvonen whenever you give a resting heart rate and says so next to the result.
Should I use a measured maximum heart rate?
If you have a reliable one, yes — it removes the largest source of error in the whole calculation. A reliable figure means the highest rate seen during an all-out effort, not a one-off spike from a slipping chest strap or a wrist sensor picking up your cadence. Without one, an age-based estimate is a reasonable starting point to be adjusted once you know how the zones actually feel.
What is each zone for?
Zone 1 is recovery and warm-up. Zone 2 is the conversational aerobic base most weekly volume should sit in, which is why it is banded on the table. Zone 3 is a moderate, steady effort. Zone 4 is comfortably hard work around the threshold where lactate starts outpacing clearance. Zone 5 is short, hard intervals near maximum. The boundaries are conventional percentage splits, not physiological measurements of your own thresholds.
Why are my zones different from my watch?
Watches differ in the maximum they assume, the percentages they assign to each zone, and whether they use heart rate reserve or plain percentage of max. Some also estimate zones from a lactate threshold they infer from your runs rather than from percentages at all. None of this makes either set wrong; they are different conventions. Pick one and stay with it, because the comparison that matters is against your own previous sessions.