Free Target Heart Rate Calculator

What is Heart Rate?

Heart rate is a measure of the number of contractions the heart makes per minute. It is measured in beats per minute (bpm). To effectively use this target heart rate calculator, it is important to understand the concepts of resting heart rate, maximum heart rate, and heart rate reserve.

Maximum Heart Rate

Maximum heart rate is a measure of the highest number of beats per minute the heart reaches during intense exercise. It is most accurately measured through a cardiac stress test, which typically involves exercising on a treadmill while being monitored by an electrocardiogram (ECG). As the subject walks/runs on the treadmill, the intensity is periodically increased until certain changes in heart function indicating maximum heart rate are detected.

More commonly, maximum heart rate is estimated using various formulas. It is worth noting that maximum heart rate formulas have been criticized as inaccurate as they output generalized population averages and estimates can vary significantly from an individual's maximum heart rate. Maximum heart rate is largely correlated with age, and most formulas are primarily based on this.

Maximum Heart Rate Formulas

Resting Heart Rate

Resting heart rate is a measure of a person's heart rate at rest, where rest is defined as when a person is awake in a neutral environment that is neither too hot nor cold, and the person is not subject to stress or surprise. It can be measured using a variety of devices or just by counting your pulse over a minute.

A typical resting heart rate (RHR) for an adult ranges between 50-90 bpm. A resting heart rate above the upper range is referred to as tachycardia while one below the lower range is referred to as bradycardia. A RHR in the 50-60 range in some cases may be considered bradycardia, but very fit athletes often have RHRs in this range, and sometimes even below.

Heart Rate Reserve

A person's heart rate reserve (HRR) is the difference between their maximum heart rate (MHR) and their resting heart rate (RHR):

For example, given a person has a maximum heart rate of 180 bpm and a resting heart rate of 68, their heart rate reserve is:

HRR = 180 - 68 = 112 bpm

Target Heart Rate Zones

There are various methods used to measure intensity of exercise in relation to heart rate. Generally, the more intense the exercise, the higher the heart rate. Maintaining a heart rate within a certain range, referred to as the target heart rate (or training heart rate range), has been found to be beneficial for exercise.

If a person exercises too high above their target heart rate zone, they may expend excess energy without much benefit and risk injury and a longer recovery time. On the other hand, exercising too far below their target heart rate zone may provide little to no benefit.

Methods for Measuring Intensity

Haskell & Fox Exercise Zone Method

This method for calculating target heart rate zones is one of the most straightforward and widely used methods and is based only on maximum heart rate computed using age. This is the method used by the calculator when only an age and no resting heart rate is entered.

The formula used for determining maximum heart rate with this method is:

The target heart rate zone is then found by multiplying MHR by the desired percentages. For example, given that a person is 36 years old, their MHR can be calculated as:

MHR = 220 - 36 = 184 bpm

Then, if they wanted to find a target heart rate zone for moderate exercise (70-80%), they would multiply:

184 × 0.70 = 129 bpm (lower bound)
184 × 0.80 = 147 bpm (upper bound)

Karvonen Method

The Karvonen method calculates target heart rate zone using heart rate reserve (HRR), which factors in resting heart rate (RHR) on top of maximum heart rate (MHR) rather than just MHR. This is the default method used by the calculator when a resting heart rate and age are entered.

For example, given that we want to find the 70%-80% target heart rate zone for a 36-year-old with a resting heart rate of 70 bpm:

HRR = 184 - 70 = 114
HR at 70% = (0.70 × 114) + 70 = 150 bpm
HR at 80% = (0.80 × 114) + 70 = 161 bpm

Thus, their 70-80% target heart rate zone is 150-161 bpm.

Rating of Perceived Exertion (RPE)

Rating of perceived exertion (RPE) is an indicator of exercise intensity that allows a person to subjectively rate their level of exertion while exercising. This is beneficial because it doesn't require measurement of physiological parameters such as heart rate. Studies have shown that individuals are able to accurately estimate subjective terms like "moderate" and "intense" and exercise at the designated level.

Borg Scale (6-20)

The Borg scale is the original RPE scale and ranges from 6-20, where 6 indicates no exertion and 20 indicates maximum exertion. The scale is designed such that each value, multiplied by 10, approximates heart rate at that given exertion level.

RPE	Intensity
6	No exertion at all
7-8	Extremely light
9-10	Very light
11-12	Light to Moderate
13-14	Somewhat hard
15-16	Hard
17-18	Very hard
19-20	Extremely hard to Maximal

Borg CR10 Scale (0-10)

The Borg CR10 scale is the modified version of the Borg scale on a scale of 0-10. 0 represents no exertion at all while 10 represents the strongest exertion an individual has experienced.

RPE	Intensity
0	No exertion
1	Very light
2	Light
3	Moderate
4	Somewhat difficult
5-6	Difficult
7-8	Very difficult
9	Almost maximal
10	Maximal

Tips for Accurate Measurements

• Measure resting heart rate first thing in the morning — before getting out of bed, in a relaxed state.
• Take multiple readings — measure over several days and use the average for more accuracy.
• Use a heart rate monitor during exercise — chest straps tend to be more accurate than wrist-based monitors.
• Consider a fitness test — for serious athletes, a VO2 max test can provide more precise training zones.
• Adjust for medications — beta blockers and other medications can affect heart rate; consult your doctor.