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Heart Rate Calculator

Your maximum heart rate is estimated as 208 - 0.7 × age, and training zones are set as percentages of your heart rate reserve (max minus resting). For a 38-year-old with a resting rate of 62 bpm, max is about 181 bpm and Zone 2 endurance training is 134 to 146 bpm.

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yrs
bpm
Maximum heart rate181 bpm
Heart rate reserve119 bpm
Zone 1 Recovery122 to 134 bpm
Zone 2 Endurance134 to 146 bpm
Zone 3 Tempo146 to 158 bpm
Zone 4 Threshold158 to 169 bpm
Zone 5 Maximum169 to 181 bpm

Tanaka maximum (208 - 0.7 × age), Karvonen heart-rate reserve zones.

How to use the Heart Rate Calculator

  1. Enter your age.
  2. Enter your resting heart rate, measured on waking before you get up.
  3. Read your estimated maximum heart rate.
  4. Use the five zones, in beats per minute, to set the intensity of each workout.

Formula

Max HR = 208 - 0.7 × age · Target HR = resting HR + (max HR - resting HR) × intensity

Maximum heart rate uses the Tanaka equation, which is more accurate across ages than 220 - age. Zones use the Karvonen heart-rate-reserve method: 50-60%, 60-70%, 70-80%, 80-90% and 90-100% of reserve.

The five training zones

  • Zone 1, recovery (50-60%): warm-ups, cool-downs and easy days.
  • Zone 2, endurance (60-70%): long, conversational aerobic work that builds your base.
  • Zone 3, tempo (70-80%): comfortably hard, steady efforts.
  • Zone 4, threshold (80-90%): hard efforts near lactate threshold.
  • Zone 5, maximum (90-100%): short intervals at all-out effort.

Resting heart rate guide

  • Typical adults: 60 to 100 bpm.
  • Fit and endurance-trained adults: often 40 to 60 bpm.
  • Measure for 60 seconds on waking on three to five mornings and average the readings.

Heart Rate Calculator questions

What are the heart rate training zones?

There are five: Zone 1 recovery (50-60%), Zone 2 endurance (60-70%), Zone 3 tempo (70-80%), Zone 4 threshold (80-90%) and Zone 5 maximum effort (90-100%). Lower zones build aerobic fitness and recovery; higher zones build speed and power but need more rest afterwards.

How do I calculate my maximum heart rate?

The simplest estimate is 220 - age; the Tanaka formula, 208 - 0.7 × age, is more accurate for most adults and is what this calculator uses. For a 40-year-old both give 180 bpm. Individual maximums can differ by 10 bpm or more, so a supervised test gives the true value.

What is the Karvonen method?

The Karvonen method sets zones using heart rate reserve, the gap between your maximum and resting heart rate: target = resting + (max - resting) × intensity. Because it accounts for resting rate, it gives more personal zones than a plain percentage of maximum, especially for fit people.

Which heart rate zone burns the most fat?

Zone 2 (60-70%) burns the highest share of calories from fat, and you can sustain it for long sessions. Higher zones burn more total calories per minute, though, so the best plan for fat loss mixes plenty of Zone 2 with some harder sessions and an overall calorie deficit.

How do I measure my resting heart rate?

Measure it as soon as you wake up, before getting out of bed. Count your pulse at the wrist or neck for 60 seconds, or for 15 seconds and multiply by 4. Repeat on three to five mornings and use the average.

How much time should I spend in each zone?

Many coaches recommend roughly 80% of training time at low intensity (Zones 1 and 2) and 20% at moderate to high intensity (Zones 3 to 5). This 80/20 approach builds aerobic fitness while limiting fatigue and injury risk. Beginners can start with almost all easy training.

What affects my heart rate during exercise?

Heat, dehydration, caffeine, stress, poor sleep, illness, altitude and some medications all raise heart rate at the same pace. Beta blockers lower it. On hot days your heart rate can run 10 bpm or more higher, so adjust effort rather than chasing a number.

How accurate are fitness tracker heart rate readings?

Chest straps are the most accurate for exercise. Wrist-based optical sensors are good during steady activity but can lag or misread during intervals, weightlifting and cold weather. For zone training, use a chest strap if precision matters.

Should I recalculate my zones as I get fitter?

Yes. Your maximum heart rate changes little with fitness, but your resting rate usually falls. Re-measure your resting heart rate every few months and update it here; a lower resting rate widens your reserve and shifts every zone.