How Accurate is the Apple Watch Calories During Workout Feature?

If you’re an Apple Watch owner, you may have wondered how accurate the calorie-tracking feature is during workouts. Here’s what we found.


The Apple Watch is an amazing device that has revolutionized the way we measure our physical activity on a regular basis. An essential part of fitness tracking is the ability to accurately measure calories burned during a workout. This article will explore how accurate the Apple Watch calorie calculation feature is and what elements contribute to its accuracy. We will also look into any advice or tips to ensure maximum accuracy when using the calorie measurement feature of an Apple Watch. By taking into account these factors, readers should be able to accurately gauge how many calories they are burning during their workouts with their Apple Watch.

How the Apple Watch Calculates Calories

The Apple Watch has a feature where it can measure the calories burned during a workout. It does this by measuring your heart rate, activity, and environmental factors. This information is then used to estimate the total amount of calories you burned. With this feature, you can estimate how many calories you’re burning during your workout and track your progress. So, how accurate is this feature? Let’s take a look.

Heart Rate Sensor

The Apple Watch uses the built-in heart rate sensor to measure your calorie burn during a workout. The watch monitors your heart rate by using green LED lights combined with light-sensitive photo diodes on the back of the watch. When worn tight enough, the watch can detect your pulse and calculate an accurate calorie count.

The Apple Watch also incorporates physical activity data that you enter beforehand, such as age, height, weight and sex to further determine an exact number of calories burned. In addition, it takes into consideration factors that are unique to each user: fitness levels, training intensities and individual fitness levels all play a role in determining how accurate your calorie count is.

The Apple Watch also utilizes motion sensor technology from Apple’s M9 motion coprocessor in order to automatically track steps, stairs climbed and more. All this data allows for an even more precise reading of calories burnt during workouts, as well as throughout the day when wearing the watch.

Apple has tuned their algorithms for accuracy based on feedback from users and clinical studies conducted by leading medical experts. By continuously refining this information through studies and user input the accuracy of their monitoring technology is constantly becoming increasingly more reliable over time.

Motion Sensor

The Apple Watch utilizes its built-in motion sensors, including an accelerometer and gyroscope to accurately measure activity. These sensors work together to detect your body’s movements, such as walking and running, in order to determine your calorie burn rate.

The motion sensor can also detect a range of different exercises, from swimming, cycling and step counting to yoga, dance and endurance training. This allows the Apple Watch to measure heart rate as well as body motion while tracking and calculating calories burned during every workout session or activity done with the watch on your wrist.

Moreover, the calorie calculation is based on height and weight data which can be entered manually in the app. By collecting these data points along with the sensed movement information gathered through its sensory system, the Apple Watch arrives at an estimation that is much more accurate than generic charts.


The Apple Watch uses two accurate ways to measure calorie burn while you work out: your heart rate, and an accelerometer. The accelerometer measures how much force is generated during your workout by measuring the body’s acceleration as it changes position. This can be used to measure duration, speed, distance, gait (steps/minute), and aerobic capacity of a user’s exercise session.

The fact that the Apple Watch has an accelerometer allows it to track activities such as running, biking, and walking with remarkable accuracy. Additionally, it can sense other kinds of motion too — like when you’re skiing down a mountain or swimming laps in a pool — and convert this information into calorie burn estimates.

The most accurate way for the Apple Watch to calculate calorie burn is through its heart rate measurement system. But when you’re not wearing a heart rate monitor (which can be uncomfortable during some types of workouts) or you’re doing activities where tracking your heart rate isn’t feasible — like yoga or weightlifting — the accelerometer will kick in and provide your estimated caloric expenditure.

Accuracy of Apple Watch Calories During Workout

The Apple Watch is known for its accuracy when it comes to tracking health and fitness information. One of the features it’s most known for is its ability to accurately track calories burned during workouts. But how accurate is it really? We’ll be taking a look at the accuracy of the Apple Watch when it comes to tracking the calories burned during workouts.

Studies on Accuracy

Existing research indicates that the Apple Watch is capable of providing an accurate assessment of calorie output during a workout. This can be seen in a study published in the Journal of Medical Internet Research which compared the calories burned readings on the Apple Watch to those obtained by a specialized metabolic cart while subjects performed moderate-intensity cycling. The study found that all participants had their calories burned readings within 4% accuracy of the reference measured by the metabolic cart, and that was achieved with no additional input required from subjects – indicating that the device proved to be reliable for easier monitoring.

In 2017, an accuracy test was conducted at Stanford University Medical Center comparing data from different consumer wearable devices such as FitBit and Apple Watch to laboratory measurements. It showed that AppleWatch workouts were accurate in energy calculations and heart rate between 98% -99%. According to this one-year Stanford study, when it comes to tracking calories burned during workouts, Apple Watches were impressive — slightly better than some other brands, but about even overall with watches from Fitbit, Mio and Garmin.

A study conducted Edge Hill University further validated these findings: results showed a high degree of agreement in calorie expenditure betweenApple watch and metabolic measure as well as encouraging evidence of reliability when looking at consecutive days. This suggests devices such as Apple watch can track physical activity (in terms of energy expended) accurately making it useful tool for meeting physical activity guidelines or monitoring increases (or decreases) in physical activity levels over time.

Factors Affecting Accuracy

Calories burned during workouts can vary greatly depending on a number of factors. These include age, gender, weight, body composition, type of exercise, intensity level of exercise and duration of the workout. Because these variables can change from person to person and from session to session it can be difficult for an individual’s Apple Watch (or any fitness tracking device) to accurately calculate calorie burn for every given workout.

The same holds true when measuring calorie burn with the Apple Watch feature “Calories During Workout”. The feature records the active calories you burn—the amount you burn above your resting rate— over a certain exercise period such as 30 minutes or 1 hour. Although the Apple Watch provides an estimate based on your sex, age, height and weight that have been entered into your Health profile (in accordance with common formulas assessing BMR), this metric may still not be 100% accurate due to other influencing factors mentioned above.

In order for a more accurate assessment of calorie burn during exercise more than just your vital information should be taken into consideration. This includes an individual’s heart rate throughout their workout as well as a comprehensive analysis of their current diet and overall lifestyle habits taken from a self-assessment questionnaire. By taking into account important metrics such as these one can achieve more accuracy in determining their caloric expenditure during exercise-based activities using their Apple Watch or other fitness tracking device.


In conclusion, the accuracy of the calorie count on an Apple Watch during workouts is generally quite accurate. The Apple Watch uses calorie estimates that are based on your age, weight, gender, and heart rate to determine how many calories you are burning during your workout. While this estimate is often quite accurate and reliable, it may not be spot-on every time. To accurately measure the number of calories burned, users should take into account their own individual characteristics when estimating their calorie counts. Additionally, those seeking exact measurements can pair their Apple Watch with additional fitness tracking devices or specialized heart-rate monitors for an even more precise result.

Checkout this video:

Similar Posts