What is the fat-burning zone?

Zone 2 (60–70% of max HR) is labeled the 'fat-burning zone' because the body oxidizes a higher proportion of fat for fuel at moderate intensities compared to glucose. However, what actually drives fat loss is total calorie deficit, not the ratio of fat to carbs burned during exercise. Zone 2 is excellent for building aerobic capacity and health, but high-intensity training burns more total calories per minute.

Should all my workouts be in Zone 2?

No. Smart endurance training mixes zones — longer Zone 2 sessions build aerobic base and capillary density, shorter Zone 4–5 intervals build top-end power and VO₂ max. The '80/20 rule' is popular with endurance athletes: 80% of training volume in Zones 1–2, 20% in Zones 4–5, with minimal time in Zone 3 (often called the 'junk miles' zone).

What is the Karvonen method?

A more personalized heart-rate zone formula developed by Finnish researcher Martti Karvonen. It uses heart-rate reserve (max HR − resting HR) instead of just max HR, which better accounts for individual fitness. Fit people with lower resting HR get higher absolute target zones, matching their actual aerobic capacity. It is the preferred method for serious endurance athletes.

How do I measure my resting heart rate?

First thing in the morning, lying still in bed before getting up. Take your pulse for 60 seconds (or use a fitness watch or chest strap). Below 60 bpm generally indicates good cardiovascular fitness; elite endurance athletes often see 40–50 bpm. Very high resting HR (above 90) may warrant medical evaluation, especially if accompanied by other symptoms.

Should I worry if my heart rate hits Zone 5 during easy exercise?

It may indicate high caffeine intake, dehydration, recent illness, chronic stress, poor sleep, or general unfitness. Occasional spikes are normal; a persistent pattern of easy efforts feeling like maximum efforts warrants attention. Consult a doctor if it happens repeatedly, or if it comes with dizziness, chest pain, or shortness of breath.

How do I use zones practically during a workout?

Wear a heart-rate monitor (chest strap for accuracy, wrist for convenience). Target the zone appropriate for your session: Zone 2 for base endurance runs, Zone 3 for tempo runs, Zone 4 for threshold intervals, Zone 5 for short max-effort repeats. Check your watch periodically and adjust pace to hold the target zone.

Do zones apply to strength training?

Zones are designed for steady-state cardio and intervals. During strength training, heart rate spikes during sets (often into Zone 4–5) and drops during rest — this is normal and not 'cardio training' in the zone sense. Don't use cardio zone targets for weightlifting sessions; use set/rep schemes and load progression instead.

Heart Rate Zone Calculator

Health

Calculate your max heart rate and five training zones for cardio workouts.

Health

Heart Rate Zone Calculator

Generated on April 24, 2026

Age (years)

Resting HR (bpm, optional)

?What is the Heart Rate Zone Calculator?

A heart-rate zone calculator determines your maximum heart rate and the five training zones used in cardiovascular programming. Training in specific zones targets different physiological adaptations — Zone 2 builds aerobic base and fat-burning efficiency, Zone 4 develops lactate threshold, Zone 5 maximizes VO₂ max and power. Whether you run, cycle, row, or swim, knowing your zones and sticking to them in each session makes your training dramatically more effective than simply 'going hard' every day. This tool supports both the standard formula and the more personalized Karvonen method.

The Formula

Max HR = 220 − age. Karvonen method: Target HR = Resting HR + (Max HR − Resting HR) × Intensity %.

The traditional '220 − age' formula estimates maximum heart rate — a population average derived from exercise physiology studies, accurate within ±10–15 bpm for most adults. The Karvonen method is more personalized: it uses heart-rate reserve (max HR minus resting HR) to calculate zones, which means fitter people (who have lower resting heart rates) get appropriately higher absolute target zones. Training zones are then defined as percentages of either max HR or heart-rate reserve.

Practical Examples

Age 30 with resting HR 60 bpm gives max HR 190. Zone 2 (60–70% intensity): 138–151 bpm — the aerobic fat-burning zone.

Age 45 with resting 70 gives max HR 175. Zone 4 (80–90%): 154–164 bpm — lactate threshold training, high but sustainable.

Age 25 with resting 55 gives max HR 195. Zone 5 (90–100%): 181–195 bpm — maximum effort, short intervals only.

Age 50 walker has target 98–114 bpm in Zone 1–2 for a recovery pace or brisk walk — perfect for overall health and longevity.

A 35-year-old runner at 65 bpm resting training in Zone 2 aims for 134–147 bpm — the conversation-pace zone used by elite endurance athletes for base mileage.

HIIT intervals typically push into Zone 4–5 briefly (1–4 minutes) with Zone 1–2 active recovery between — a pattern backed by extensive research for time-efficient fitness gains.

Frequently Asked Questions

It's a rough population average with ±10–15 bpm variance between individuals. Some people truly have a max HR of 200 at age 40; others legitimately max at 175. For precision, an exercise stress test in a clinical setting gives exact max HR. For everyday training, 220 − age is a reasonable starting point that can be refined over time by observing your actual peak HR during all-out efforts.

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Heart Rate Zone Calculator

Heart Rate Zone Calculator

?What is the Heart Rate Zone Calculator?

The Formula

Practical Examples

Frequently Asked Questions

Is '220 − age' actually accurate?

What is the fat-burning zone?

Should all my workouts be in Zone 2?

What is the Karvonen method?

How do I measure my resting heart rate?

Should I worry if my heart rate hits Zone 5 during easy exercise?

How do I use zones practically during a workout?

Do zones apply to strength training?

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