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. The theoretical maximum human heart rate is 300 bpm.
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. Thus, while they are generally useful for estimating the average maximum heart rate for a given age group, the heart rate of an individual within the age group can differ significantly. One interesting observation made by Dr. Fritz Hagerman was that the maximum heart rates of a group of men in their 20s who were on Olympic rowing teams varied between 160 and 220 beats per minute, so even at the elite level, there is significant variability.
The following are some formulas used to estimate maximum heart rate.
Haskell & Fox Formula (1971):
maximum heart rate = 220 - age
Tanaka, Monahan, & Seals Formula (2001):
maximum heart rate = 208 - 0.7 × age
Nes, Janszky, Wisloff, Stoylen, Karlsen Formula (2013):
maximum heart rate = 211 - 0.64 × age
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 (or extrapolating it based on a shorter period, though this is less accurate).
A typical resting heart rate (RHR) for an adult ranges between 50-90 bpm. Some sources state this range as 60-100 bpm, but this range is slightly dated. 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 (HRreserve) is the difference between their maximum heart rate (MHR) and their resting heart rate (RHR):
HRreserve = MHR - RHR
For example, given a person has a maximum heart rate of 180 bpm and a resting heart rate of 68, their heart rate reserves is:
HRreserve = 180 - 68 = 112
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. Most methods of measuring intensity relate heart rate to various degrees of physical exertion. 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.
A person's target heart rate zone is typically broken up into five zones which impart different benefits. The figure below depicts some guidelines for the range within which to maintain target heart rate for various exercise benefits:
Zone 1 refers to the lowest target heart rate zone (50-60%) while zone 5 refers to the 90-100% range. Generally:
Zone 1: This zone generally involves light to moderate activity and your heart rate may stay within this range during warm up, cooldown, a rest day, or an easy training day.
Zone 2: This zone is helpful for fat burning and training endurance. It is a zone that requires some effort but can still be maintained for extended periods of time.
Zone 3: This zone requires more effort to maintain and can help with building speed and strength.
Zone 4: This zone is close to your maximum effort and can help with training how long you can maintain your maximum output.
Zone 5: This zone represents your maximum effort. It is a zone that can be sustained for only a short duration. Training in this zone can help with improving muscle efficacy and improving overall cardiovascular fitness, but it should be balanced with sufficient recovery time. A person should not only train within this zone.
Each zone has its training benefits, so it is important to design your workout around these zones to best balance improvement and recovery.
Methods for measuring intensity
Because there is no consensus on how to measure intensity and there are many methods for determining target heart rate zones, our calculators allow you to select from various heart rate estimation methods as well as intensity scales.
Haskell & Fox Exercise Zone
A simple and widely adopted way to determine target heart‑rate zones relies solely on the age‑based estimate of maximum heart rate. The calculator applies this approach whenever the user supplies an age but omits a resting heart‑rate value. While its ease of use makes it a favorite, the method can be quite imprecise, as noted in the "Maximum heart rate" discussion above. The equation employed to compute the maximum heart rate in this scenario is:
MHR = 220 - age
To obtain the target zone, the maximum heart rate (MHR) is multiplied by the chosen percentage range. For instance, for a 36‑year‑old individual, the MHR would be computed as follows:
MHR = 220 - 36 = 184
Then, if they wanted to find a target heart rate zone for moderate exercise, they would multiply this MHR by 0.70 and 0.80 to find their target heart rate in the 70-80% range:
184 × 0.70 = 129
184 × 0.80 = 147
Consequently, a moderate‑intensity workout would correspond to a heart‑rate interval of 129‑147 bpm. This technique can be applied to derive any target zone. In practice, the target range is typically set between 50 % and 85 % of the maximum heart rate.
Beyond the basic age‑based equation, the tool also offers two alternative age‑only formulas – the Tanaka‑Monahan‑Seals model and the Nes‑Janszky‑Wisloff‑Stoylen‑Karlsen model. Both appear in the "Maximum heart rate formulas" section, and the subsequent calculation of target zones follows the same procedure.
Karvonen method
The Karvonen approach determines target zones by employing heart‑rate reserve (HRreserve), which incorporates both resting heart rate (RHR) and maximum heart rate (MHR) rather than relying on MHR alone. This algorithm becomes the calculator’s default whenever the user provides both age and resting heart rate. Users may tweak the estimation equation and intensity percentages via the options at the bottom of the tool. HRreserve is derived with this formula:
HRreserve = MHR - RHR
After obtaining HRreserve, the target zone is computed similarly to the previous description, but the chosen percentage band is applied to HRreserve instead of MHR, after which the resting heart rate is added to both limits. For instance, to identify the 70 %–80 % zone for a 36‑year‑old whose resting rate is 70 bpm:
HRreserve = 184 - 70 = 114
HR70% = 0.70 × 114 + 70 = 150
HR80% = 0.80 × 114 + 70 = 161
Thus, their 70-80% target heart rate zone is 150-161 bpm.
Rating of perceived exertion
The rating of perceived exertion (RPE) provides a subjective gauge of workout intensity, letting individuals assess how hard they feel they are working. Its advantage lies in eliminating the need for physiological measurements like heart rate or lactate concentration. Research indicates that people can reliably distinguish descriptors such as "moderate" or "intense" and adjust their effort accordingly.
There are two commonly used RPE scales: the Borg scale and the Borg category ratio 10 scale (Borg CR10 scale).
Borg scale:
The original RPE instrument, the Borg scale, spans numbers 6 to 20, with 6 signifying minimal effort and 20 representing maximal effort. It was calibrated so that multiplying a rating by 10 yields an approximate heart‑rate value for that intensity. Thus, a rating of 6 aligns with roughly 60 bpm, while 20 aligns with about 200 bpm. The following table illustrates the Borg scale:
| RPE scale | Intensity |
|---|---|
| 6 | No exertion at all |
| 7 | Extremely light |
| 9 | Very light |
| 11 | Light |
| 12 | Moderate |
| 13 | Somewhat hard |
| 15 | Hard |
| 17 | Very hard |
| 19 | Extremely hard |
| 20 | Maximal exertion |
Using this scale, target heart rate is calculated using the formula,
THR = RHR + (MHR - RHR) × B - 614
where:
- THR = target heart rate
RHR = resting heart rate
MHR = maximum heart rate
B = RPE scale value
For example, given a "somewhat hard" exertion which has an RPE scale value of 13, a person who has a maximum heart rate of 190 and a resting heart rate of 60 would have a target heart rate of:
THR = 60 + (190 - 60) × 13 - 614 = 125 bpm
Borg CR10 scale:
The Borg CR10 is a simplified adaptation of the original Borg scale, ranging from 0 to 10. A score of 0 denotes no effort whatsoever, whereas 10 corresponds to the most intense exertion a person can imagine. The CR10 scale appears below:
| RPE scale | Intensity |
|---|---|
| 0 | No exertion |
| 0.5 | Noticeable |
| 1 | Very light |
| 2 | Light |
| 3 | Moderate |
| 4 | Somewhat difficult |
| 5 | Difficult |
| 7 | Very difficult |
| 9 | Almost maximal |
| 10 | Maximal |
Using this scale, the target heart rate can be calculated using the formula,
THR = RHR + (MHR - RHR) × B10
where:
- THR = target heart rate
RHR = resting heart rate
MHR = maximum heart rate
B = RPE scale value
For example, given a "somewhat difficult" exertion which has an RPE scale value of 4, a person who has a maximum heart rate of 190 and a resting heart rate of 60 would have a target heart rate of:
THR = 60 + (190 - 60) × 410 = 112 bpm