Target Heart Rate Percentage Calculator

Hit the exact heart rate your workout is aiming for.

Result

126 bpm
180 bpm

How it is calculated

You enter your age in years and the percentage of your maximum heart rate that you want to train at. The tool first estimates the maximum with the simple age formula max HR = 220 − age, then multiplies it by the percentage: target HR = max HR × percent ÷ 100. Both results are shown in beats per minute (bpm), rounded to whole numbers. Age must be above 0 and below 120, and the percentage must be above 0 and no more than 100. You cannot type in a known maximum from a test: the tool always derives it from age with the 220 formula, which can be many beats off for an individual. Resting heart rate is not used, so this is not the Karvonen reserve method.

Worked example

A 40-year-old wants to train at 70 % of maximum. Estimated maximum: 220 − 40 = 180 bpm. Target: 180 × 70 ÷ 100 = 126 bpm, which is exact here. At 85 % the target would be 180 × 0.85 = 153 bpm. So a steady aerobic session should keep the heart rate near 126 bpm, and a hard interval should reach about 153 bpm. Both are guides, and the tool prints the 180 bpm maximum next to them so you can see what it assumed.

Try this example →

Common mistakes

  • Typing a measured maximum heart rate into the age field. The tool wants your age and will compute its own maximum.
  • Entering the percentage as a fraction (0.7) instead of 70. A value of 0.7 means 0.7 percent and gives a target of about 1 bpm.
  • Using a percentage above 100. The tool gives no result, because no one trains above their maximum.
  • Assuming the target is based on resting heart rate. It is a plain percentage of the maximum, so fit people with a low resting rate will find the zones feel different.
  • Treating the 220 minus age maximum as exact. For some people it is 10 beats or more off, which moves every zone with it.

About this calculator

Once maximum heart rate is known (or estimated from age), a target heart rate is simply a chosen percentage of that ceiling — for example, 70% of a 190 bpm max HR gives a target of 133 bpm. Exercise physiologists define standard training zones by these percentages: roughly 50–60% for warm-up and recovery, 60–70% for fat-burning and base endurance, 70–80% for aerobic/tempo training, 80–90% for VO2max and lactate-threshold intervals, and 90%+ for maximal anaerobic efforts — each zone stimulating a different physiological adaptation.

Personal trainers, cardiac rehabilitation programs and endurance coaches all prescribe workouts by target heart rate percentage rather than pace or power alone, because heart rate responds consistently to physiological strain across different activities and adjusts naturally for heat, fatigue and altitude in ways a fixed pace target can't. Wearable fitness trackers use the same percentage-of-max-HR zones to color-code workout intensity in real time, letting an athlete stay in a specific zone throughout a session.

This calculator takes your age and a chosen target percentage, estimates your maximum heart rate as 220 minus your age, and returns that maximum along with the exact beats-per-minute you should aim for, so you can train precisely within the zone your workout calls for. If you know your own measured maximum, multiply it by the percentage yourself instead.

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