Zone 2 Cardio Calculator

What is zone 2 cardio?

Zone 2 cardio is steady, easy aerobic exercise: the second of five heart-rate training zones, usually 60–70% of your maximum heart rate. Physiologists describe it as low-intensity exercise below the lactate threshold, the point where lactate starts to build up in your blood (Storoschuk et al., 2025). In everyday terms it is the pace you could hold for an hour while still chatting with a friend.

Zone 2 became popular because of endurance athletes. Studies of national and international level endurance athletes show they do roughly 80% of their training sessions at low intensity and only about 20% hard (Seiler, 2010). For the rest of us, zone 2 is simply an approachable, repeatable way to get our weekly cardio without feeling wrecked.

How this zone 2 heart rate calculator works

Enter your age, and if you know them, your resting and maximum heart rate. The calculator shows your zone 2 range with three methods side by side:

• % of max heart rate. Zone 2 = 60–70% of your maximum heart rate. Max heart rate is estimated as 220 − age, or with the newer Tanaka formula, 208 − 0.7 × age, which came out of a meta-analysis of 351 studies and was confirmed in a lab study of 514 healthy adults (Tanaka et al., 2001). If you know your real max, use it.
• Heart-rate reserve (Karvonen). Uses the gap between your resting and maximum heart rate: resting HR + 60–70% × (max HR − resting HR) (Karvonen et al., 1957). Because it includes your resting pulse, it adapts better to your fitness.
• MAF 180 formula. A different approach from coach Phil Maffetone: 180 − age, adjusted for your training history and health, as a ceiling for aerobic training (Maffetone). It is not a percentage zone, so we show it separately.

Example, age 40, resting HR 60: max HR 220 − 40 = 180 → zone 2 by % of max = 108–126 bpm. Heart-rate reserve = 180 − 60 = 120 → 60 + 0.6 × 120 = 132 to 60 + 0.7 × 120 = 144 bpm. MAF: 180 − 40 = 140 bpm ceiling.

Different numbers from different methods are normal. Formulas describe averages, and your real heart rate can sit well above or below them. Start near the lower range and let the talk test have the final word. For more detail, see zone 2 heart rate explained or look yourself up in the zone 2 heart rate by age chart.

How to check you are in zone 2

A heart rate number is handy, but your breathing is the quickest check. The CDC’s rule of thumb is that during moderate-intensity activity you can talk but not sing, while at vigorous intensity you cannot say more than a few words without pausing for breath (CDC). Research on this “talk test” finds that comfortable speech is likely possible below the ventilatory or lactate threshold and not likely above it, and that the test works across walking, jogging, cycling and other activities (Reed & Pipe, 2014). That is exactly the boundary zone 2 sits under.

Many coaches add nose breathing as a second check: if you can keep breathing comfortably through your nose, you are not overdoing it. Use it as a practical hint rather than a precise test. Heart rate also drifts upward during long sessions, in heat, after caffeine or with poor sleep, so if your pace feels easy but your watch says zone 3, slow down a little and see how your breathing responds.

How much zone 2 cardio per week?

U.S. guidelines say adults need at least 150 minutes a week of moderate-intensity activity, such as 30 minutes on 5 days, or 75 minutes of vigorous activity, plus muscle strengthening on 2 days (CDC). Going beyond 150 minutes brings even more benefit. Zone 2 counts toward the moderate minutes, so the planner above starts with a 150-minute weekly goal. Split it however you like: 5 × 30 minutes, 3 × 50, or a long weekend walk plus shorter weekday sessions. You will find ideas in zone 2 cardio examples.

Zone 2 is a base, not the whole house

Zone 2 is easy to recover from and easy to stick with, which is its biggest strength. It is not magic, though. A 2025 review concluded that current evidence does not show zone 2 to be the optimal intensity for improving mitochondrial capacity, and that harder efforts matter for cardiometabolic health, especially if you train only a few hours a week (Storoschuk et al., 2025). A sensible plan for most people is mostly easy minutes plus a little harder work and two days of strength training. Read more in zone 2 cardio benefits and, if weight is your goal, zone 2 cardio for fat loss.

Safety first

Some medications lower your heart rate and your maximum heart rate; the American Heart Association advises people with a heart condition or on medication to ask their health care professional what their heart rate should be (American Heart Association). Beta-blockers are the best-known example. In that case the talk test and how you feel are a better guide than any formula.