Zone 2 Heart Rate Calculator

What is zone 2 heart rate?

Zone 2 heart rate is the band of beats per minute that matches steady, easy aerobic exercise. In the common five-zone model it is 60–70% of your maximum heart rate. Physiologically, the idea is to stay below the lactate threshold, where lactate starts to accumulate in your blood (Storoschuk et al., 2025). That threshold is individual, which is why every formula is only a starting point.

Method 1: percentage of maximum heart rate

Zone 2 = 0.60 × max HR to 0.70 × max HR

The classic estimate of maximum heart rate is 220 − age, the figure the American Heart Association uses in its target heart rate chart (American Heart Association). Tanaka and colleagues pooled data from 351 studies with 18,712 people and found that 208 − 0.7 × age fits better; their lab test in 514 healthy adults gave almost the same line, which did not differ between men and women or with activity level. They also concluded that 220 − age underestimates max heart rate in older adults (Tanaka et al., 2001). At 40 both formulas give 180 bpm, but at 60 the classic one gives 160 and Tanaka gives 166, so zone 2 is 96–112 vs. 100–116 bpm.

Method 2: heart-rate reserve (Karvonen)

Zone 2 = resting HR + 0.60 × (max HR − resting HR) to resting HR + 0.70 × (max HR − resting HR)

The heart-rate reserve is the difference between your resting and maximum heart rate. The method goes back to a 1957 study by Karvonen and colleagues (Karvonen et al., 1957). Because it includes your resting pulse, a fit person with a low resting heart rate gets a range that reflects their fitness. It usually gives higher numbers than the % of max method: at age 40 with a resting heart rate of 60, zone 2 is 132–144 bpm by heart-rate reserve versus 108–126 bpm by % of max.

Method 3: the MAF 180 formula

MAF heart rate = 180 − age (then adjust)

Coach Phil Maffetone’s formula gives a single number, a ceiling for aerobic training. You subtract 10 if you are recovering from a major illness or take regular medication, subtract 5 if you are injured, often ill, or just starting out, keep it as is if you have trained consistently, and add 5 after more than two years of steady progress (Maffetone). Maffetone himself notes that 180 − age is not tied to VO2max or lactate threshold; it is a practical rule. We show it as a separate, clearly labeled method.

Which method should you use?

• Only know your age? Use % of max. If you are over 50, compare with the Tanaka version.
• Know your resting heart rate? Heart-rate reserve is more personal. Enter it in the calculator.
• Have a measured max heart rate from a test or a hard race? Enter it; every method will use it.
• Methods disagree? Start near the lower range and use the talk test: full sentences = zone 2.

A lab test of your lactate or ventilatory threshold gives the most accurate answer, but you do not need one to train well. Studies of the talk test show that comfortable speech is likely possible below the ventilatory or lactate threshold (Reed & Pipe, 2014), so your breathing is a free, always-available check.

Tips for using a heart rate monitor

Chest straps respond faster and are usually more accurate than wrist sensors, especially during cycling or rowing where your wrist flexes. Expect your heart rate to creep upward during long sessions, in heat, at altitude, after caffeine and when you are stressed or tired. If that happens at an easy pace, slow down slightly rather than forcing the number. Log your sessions and average heart rate in the weekly zone 2 planner to see your trend.

Not sure how your number compares? See the full zone 2 heart rate by age chart, or get ideas for zone 2 workouts.