Target heart rate calculator

Use this target heart rate calculator to estimate your training heart rate zones from age or a tested maximum heart rate. Add a resting heart rate to use the Karvonen method or Borg scales.

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Target Heart Rate Calculator

Your heart rate is the number of times your heart beats in one minute, usually expressed as beats per minute (bpm). During exercise, your heart rate generally rises as your body works harder and requires more oxygen.

A target heart rate is a range that can be used to guide how hard you exercise. Knowing your target heart rate can help you distinguish between relatively light, moderate, and vigorous exercise.

Our Target Heart Rate Calculator estimates your maximum heart rate and calculates target heart rates using different exercise-intensity methods. Depending on the information you provide, the calculator can use your age, resting heart rate, and a selected perceived-exertion scale.

What is heart rate?

Heart rate is the number of heartbeats that occur in one minute. It is measured in beats per minute, or bpm.

Your heart rate changes throughout the day. It can increase during exercise, stress, excitement, or illness and can decrease when you are resting or sleeping.

During physical activity, monitoring your heart rate can provide an indication of how demanding the exercise is. As exercise intensity increases, heart rate generally increases as well.

Heart rate is not the same as blood pressure. Heart rate measures how frequently the heart beats, whereas blood pressure measures the force of blood against the walls of your arteries.

Maximum heart rate

Maximum heart rate (MHR) is an estimate of the highest number of times your heart can beat per minute during very intense exercise.

Maximum heart rate varies from one person to another. Two people who are the same age can have different actual maximum heart rates. For this reason, formulas based on age should be considered estimates rather than exact measurements.

One of the most widely used formulas is:

MHR = 220 − age

For example, if you are 40 years old:

MHR = 220 − 40

MHR = 180 bpm

Other formulas have also been developed to estimate maximum heart rate. Two commonly cited alternatives are:

Tanaka formula:

MHR = 208 − (0.7 × age)

Nes formula:

MHR = 211 − (0.64 × age)

Because these formulas are based on different research populations and methods, they do not necessarily produce the same result for a particular person.

Measuring maximum heart rate

The most direct way to determine maximum heart rate is through an appropriately conducted exercise test. However, deliberately exercising to maximum effort is not necessary for most people simply trying to establish a general training range.

For everyday fitness purposes, an age-based formula provides a convenient starting point.

The American Heart Association uses 220 minus age as a general estimate and notes that calculated target heart rates are averages that should be used as general guidance (www.heart.org).

Resting heart rate

Resting heart rate (RHR) is your heart rate when your body is at rest.

For many adults, a resting heart rate between 60 and 100 bpm is considered typical. People who are physically fit may have lower resting heart rates. Resting heart rate can also be affected by factors such as stress, medications, physical activity, illness, and other conditions (www.heart.org).

For a useful resting measurement, check your heart rate when you are relaxed. Measuring it in the morning before getting out of bed is one common approach.

You can measure your resting heart rate using a smartwatch or other heart-rate monitor, or by manually checking your pulse.

Resting heart rate is particularly important when using the Karvonen method, because that method takes both resting and maximum heart rate into account.

Heart rate reserve

Heart rate reserve (HRR) is the difference between your maximum heart rate and resting heart rate.

It is calculated as:

HRR = MHR − RHR

For example, suppose your estimated maximum heart rate is 180 bpm and your resting heart rate is 68 bpm:

HRR = 180 − 68

HRR = 112 bpm

Heart rate reserve represents the range between your resting heart rate and your estimated maximum heart rate.

The heart rate reserve can then be used to determine a target heart rate at a particular exercise intensity.

Target heart rate zones

A target heart rate zone is a range of heart rates associated with a particular level of exercise intensity.

One commonly used approach is to express exercise intensity as a percentage of maximum heart rate.

For example:

These ranges are useful as general training guidelines, but they should not be interpreted as precise physiological boundaries.

For general exercise, the American Heart Association describes moderate-intensity activity as approximately 50–70% of maximum heart rate and vigorous activity as approximately 70–85% (www.heart.org).

Example of a target heart rate range

Suppose a 40-year-old has an estimated maximum heart rate of 180 bpm.

A target range of 70–80% would be calculated as:

Lower target:

180 × 0.70 = 126 bpm

Upper target:

180 × 0.80 = 144 bpm

The resulting target range would therefore be approximately:

126–144 bpm

This type of calculation uses maximum heart rate directly. The Karvonen method described below uses resting heart rate as well.

Methods for measuring exercise intensity

There is more than one way to describe how hard you are exercising.

A simple method is to express exercise intensity as a percentage of maximum heart rate. Another method, known as the Karvonen method, uses heart rate reserve and therefore incorporates resting heart rate.

Exercise intensity can also be described using rating of perceived exertion (RPE). Instead of relying solely on a heart-rate reading, RPE asks you to judge how difficult the exercise feels.

Two commonly used perceived-exertion scales are:

• Borg Rating of Perceived Exertion (RPE) scale, which ranges from 6 to 20
• Modified Borg CR10 scale, which ranges from 0 to 10

These methods are useful because heart rate does not always tell the complete story. Temperature, fatigue, stress, fitness level, medications, and the type of exercise can all influence heart rate.

Maximum-heart-rate method

One straightforward approach is to first estimate maximum heart rate and then apply a desired percentage.

Using the commonly used Haskell-Fox formula:

MHR = 220 − age

The target heart rate is then:

Target HR = MHR × intensity

For example, consider a 35-year-old.

First calculate maximum heart rate:

MHR = 220 − 35 = 185 bpm

If the desired exercise intensity is 70%:

Target HR = 185 × 0.70

Target HR = 129.5 bpm

Rounded to the nearest whole number, the target heart rate is approximately 130 bpm.

If the desired intensity is 80%:

Target HR = 185 × 0.80

Target HR = 148 bpm

Therefore, the 70–80% target range would be approximately 130–148 bpm.

This method is simple because it requires only age and the desired intensity.

Karvonen method

The Karvonen method calculates target heart rate using heart rate reserve. Unlike a simple percentage-of-maximum calculation, it takes resting heart rate into account.

First calculate heart rate reserve:

HRR = MHR − RHR

Then calculate the target heart rate:

Target HR = RHR + (HRR × intensity)

For example, suppose:

• Age = 40
• Maximum heart rate = 180 bpm
• Resting heart rate = 70 bpm
• Desired intensity = 70%

First:

HRR = 180 − 70 = 110 bpm

Then:

Target HR = 70 + (110 × 0.70)

Target HR = 147 bpm

At 80% intensity:

Target HR = 70 + (110 × 0.80)

Target HR = 158 bpm

Therefore, the 70–80% target range would be approximately 147–158 bpm using the Karvonen method.

Notice that this is different from simply taking 70–80% of maximum heart rate. The difference occurs because the Karvonen calculation incorporates resting heart rate.

Rating of perceived exertion

Rating of perceived exertion (RPE) is a way of describing exercise intensity based on how difficult the activity feels.

For example, an easy walk might feel very light, while sprinting may feel extremely difficult.

RPE can be particularly useful when a heart-rate monitor is unavailable. It can also provide additional information when heart rate is affected by factors such as heat, dehydration, fatigue, stress, or medication.

The traditional Borg RPE scale ranges from 6 to 20. The modified Borg CR10 scale uses a simpler 0–10 range.

Borg RPE scale

The Borg RPE scale ranges from 6 to 20, with higher values representing greater perceived effort.

The original Borg scale was designed so that the rating could provide a rough relationship to heart rate. For example, an RPE of 13 has traditionally been associated with a heart rate around 130 bpm.

However, this relationship is only approximate. An individual’s actual heart rate at a given RPE can differ substantially.

The CDC describes the Borg RPE scale as a 6–20 scale, with 6 representing very low effort and 20 representing maximal exertion. CDC

Calculating target heart rate using Borg RPE

When the Borg scale is incorporated into a heart-rate-reserve calculation, the target heart rate can be estimated using:

Target HR = RHR + [(MHR − RHR) × (RPE − 6) / 14]

where:

• Target HR = target heart rate
• RHR = resting heart rate
• MHR = maximum heart rate
• RPE = selected Borg rating

For example, suppose:

• Maximum heart rate = 190 bpm
• Resting heart rate = 60 bpm
• RPE = 13

Then:

Target HR = 60 + [(190 − 60) × (13 − 6) / 14]

Target HR = 60 + (130 × 7 / 14)

Target HR = 125 bpm

Therefore, the estimated target heart rate for an RPE of 13 would be approximately 125 bpm.

Modified Borg CR10 scale

The Borg CR10 scale is another way to describe perceived exercise intensity. It uses a range from 0 to 10, making it somewhat simpler than the traditional 6–20 Borg scale.

The exact wording used to describe the intermediate values can vary slightly between versions of the scale.

Calculating target heart rate using CR10

When the CR10 scale is used with heart rate reserve, the target heart rate can be calculated as:

Target HR = RHR + [(MHR − RHR) × CR10 / 10]

For example, suppose:

• Maximum heart rate = 190 bpm
• Resting heart rate = 60 bpm
• CR10 rating = 4

Then:

Target HR = 60 + [(190 − 60) × 4 / 10]

Target HR = 60 + 52

Target HR = 112 bpm

The estimated target heart rate is therefore 112 bpm.

A CR10 value of 4 represents an exercise effort described as somewhat difficult.

Why can different methods give different results?

It is normal for different target heart rate methods to produce different numbers.

The maximum-heart-rate approach uses a percentage of estimated maximum heart rate. The Karvonen method additionally considers resting heart rate. RPE methods attempt to relate perceived effort to exercise intensity.

For example, two people who are the same age may have the same estimated maximum heart rate but different resting heart rates. Their heart rate reserves will therefore differ, leading to different Karvonen target heart rates.

Similarly, two people performing the same workout may report different perceived exertion because of differences in fitness, fatigue, training experience, or other circumstances.

For this reason, target heart rate should be viewed as a guide to exercise intensity rather than an exact number that applies equally to everyone.

How to check your heart rate

You can monitor your heart rate during exercise using a smartwatch, fitness tracker, chest strap, or exercise machine with a heart-rate sensor.

You can also measure your pulse manually.

To check your pulse at your wrist:

1. Place your index and middle fingers on the inside of your wrist, near the base of your thumb.
2. Press gently until you feel the pulse.
3. Count the beats for 60 seconds.
4. The number of beats is your heart rate in bpm.

You can also count for 30 seconds and multiply the result by two. The American Heart Association describes this as one way to manually calculate beats per minute (www.heart.org).

Factors that can affect heart rate

Exercise intensity is not the only factor that determines heart rate. Your heart rate can also be affected by:

• Age
• Fitness level
• Temperature and humidity
• Hydration
• Stress and anxiety
• Sleep and fatigue
• Caffeine and other stimulants
• Illness
• Medications
• Type of exercise
• Training experience

Consequently, your heart rate during the same workout can vary from one day to another.

Target heart rate is an estimate

Age-based formulas are useful because they provide a simple way to estimate maximum heart rate, but they cannot determine an individual’s actual maximum with precision.

The American Heart Association describes age-based target heart-rate values as averages and recommends using them as general guidance (www.heart.org).

Your perceived effort and other factors should therefore be considered alongside the number displayed by a heart-rate monitor.

Important note

The results provided by this calculator are estimates intended for general informational and fitness purposes. They should not be considered a diagnosis or a substitute for individualized medical advice.

Age-based maximum heart rate formulas are estimates, and actual maximum heart rate can vary substantially between individuals. If you have a cardiovascular or other medical condition, take medication that affects your heart rate, or experience unusual symptoms during exercise, consult a qualified healthcare professional before beginning or changing an exercise program.