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Max Heart Rate Calculator

Find your maximum heart rate using the NTNU formula — the most accurate age-based equation available — and see your five personalised training zones.

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What Is Maximum Heart Rate?

Maximum heart rate (HRmax) is the highest number of times your heart can beat per minute during all-out physical effort. It is the ceiling of your cardiovascular capacity and serves as the reference point for all heart rate training.

HRmax is primarily determined by age — it declines by roughly 0.6–0.7 beats per year throughout adulthood. Fitness level, medications, and altitude can affect your working heart rate, but they do not significantly change your HRmax.

The NTNU Formula

This calculator uses the formula developed by the Cardiac Exercise Research Group at the Norwegian University of Science and Technology (NTNU):

HRmax = 211 − 0.64 × age

Published by Nes et al. in 2013, it was derived from a study of 3,320 healthy Norwegian adults and validated as more accurate than the widely used “220 − age” formula — particularly for people over 40, where the older formula consistently overestimates HRmax.

Heart Rate Training Zones

Training zones are expressed as a percentage of your HRmax. Each zone targets a different physiological system:

ZoneName% of HRmaxPurpose
Zone 1Recovery50–60%Active recovery, warm-up, cool-down
Zone 2Fat Burn60–70%Base aerobic fitness, fat oxidation
Zone 3Aerobic70–80%Sustained endurance, aerobic capacity
Zone 4Threshold80–90%Lactate threshold, race-pace training
Zone 5VO₂ Max90–100%Maximum aerobic power, speed

How to Use Your Max Heart Rate

  1. Calculate your HRmax by entering your age above.
  2. Choose a target zone based on your training goal.
  3. Monitor your heart rate during exercise using a chest strap or wrist-based heart rate monitor.
  4. Adjust intensity to keep your heart rate within the target zone.

Most endurance training plans recommend spending the majority of training time (roughly 80%) in Zones 1–2, with the remaining 20% at higher intensities — a strategy known as polarised training.

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Frequently Asked Questions

What is maximum heart rate?

Maximum heart rate (HRmax) is the highest number of beats per minute your heart can achieve during maximum physical effort. It is primarily determined by age and genetics. HRmax declines by roughly 0.6–0.7 beats per year as you get older.

Why use the NTNU formula instead of 220 minus age?

The classic '220 − age' formula (Fox, 1971) was never validated in a research study — it was a rough estimate based on a small dataset. The NTNU formula (211 − 0.64 × age) was derived from a large Norwegian study of 3,320 healthy adults and has been shown to be significantly more accurate, especially for people over 40.

How accurate is the NTNU formula?

No age-based formula is perfectly accurate for every individual because genetics cause natural variation. The NTNU formula has a standard deviation of about ±10 bpm, meaning roughly two-thirds of people will have a true HRmax within 10 bpm of the estimate. For a precise measurement, a maximal exercise test supervised by a professional is required.

What are heart rate training zones used for?

Training zones let you target specific physiological adaptations during exercise. Zones 1–2 improve base aerobic fitness and fat metabolism. Zone 3 builds sustained aerobic capacity. Zone 4 raises the lactate threshold — the point at which fatigue accumulates rapidly. Zone 5 develops maximal aerobic power (VO₂max).

Does maximum heart rate differ between men and women?

The NTNU formula applies to both men and women. Some formulas (such as the Gulati formula for women) report slightly different values, but research shows the difference is small and not clinically significant for most training purposes.