Heart rate zones

Compute your 5 training zones using the Karvonen method - more accurate than plain %HRmax.

Compute your 5 heart rate zones using the Karvonen (HR reserve) method.

Karvonen heart rate zones calculator based on age, max HR and resting HR.

Karvonen method: zone = HRrest + %×(HRmax − HRrest). More accurate than plain %HRmax.

• Your parameters
• Age
• yrs
• Use Tanaka formula (208 − 0.7×age)
• Measured max HR
• Resting HR
• Max HR
• Reserve (HRR)
• Your 5 HR zones

The Karvonen method, and why it is more accurate

Most heart rate zone calculators apply a plain percentage of maximum heart rate: 70 percent of 190 bpm gives 133 bpm. That approach ignores one decisive input, your resting heart rate.

Karvonen works from heart rate reserve, the gap between your max HR and your resting HR. The formula is: target HR = resting HR + (max HR − resting HR) × intensity. Two runners with the same max HR, one resting at 45 bpm and the other at 70, end up with different zones, which correctly reflects the real difference in their conditioning.

The 5 zones and what each one trains

Every zone drives a distinct physiological adaptation. A well-built training week does not spread time evenly across them.

• Zone 1, 50 to 60 percent: active recovery, warm-ups and cool-downs. Very light effort.
• Zone 2, 60 to 70 percent: aerobic base. This is the zone that builds your aerobic engine, and where most of your weekly volume belongs.
• Zone 3, 70 to 80 percent: tempo, sometimes called the grey zone. Useful, but frequently overused at the expense of zones 2 and 4.
• Zone 4, 80 to 90 percent: lactate threshold. Improves your ability to hold a hard pace for a long time.
• Zone 5, 90 to 100 percent: VO2 max and maximal power. Short intervals only.

Measuring your resting heart rate properly

Take it on waking, before getting out of bed, ideally across several consecutive mornings and averaged. A reading taken during the day, after coffee or a flight of stairs, will be too high and will push every zone upward.

If you wear a watch or a band overnight, the resting heart rate it reports is usually reliable and saves you the manual routine.

Frequently asked questions

How do I find my max heart rate without a lab test?

The old 220 − age rule is widespread but imprecise, with a margin of error of ten to fifteen beats. The Tanaka formula, 208 − 0.7 × age, is statistically more reliable and is offered in the calculator. Best of all is a real measurement: after a thorough warm-up, run a hill with a progressive build to exhaustion and the peak you see will be close to your true maximum.

Karvonen or plain percentage of max HR: what changes in practice?

For a well-trained runner with a low resting heart rate, Karvonen produces noticeably higher zones than a simple percentage of max HR. The gap can reach ten beats in zone 2, which genuinely changes what the session does to you. The lower your resting heart rate, the bigger the difference.

Why does my heart rate climb late in a long run?

That is cardiac drift: at a steady pace, heart rate creeps upward as dehydration and heat accumulate. Ten beats of drift over a long run is normal. It is a good reason to run long efforts by pace or by feel rather than defending a strict heart rate ceiling.

Do I really need to run that slowly in zone 2?

Yes, and it is the most commonly ignored advice in running. Keeping most of your volume in zone 2 develops the aerobic system without piling up the fatigue that ruins your hard sessions. The classic mistake is running every session in zone 3: too hard to recover from, too easy to drive real adaptation.