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How Accurate Are Treadmill Calories?

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Many runners are interested in using running as a way to burn calories to either lose or control their weight. It’s a simple fact that the more calories you burn while running, the more weight you will lose or the more food you’ll be able to eat to maintain your weight.

But how do you know how many calories you burn running? 

Can you trust the calorie counter on a treadmill? How accurate are treadmill calories?

Depending on who you consult, it seems that everyone has a differing opinion about whether treadmill calories are accurate. Some say that treadmill calorie estimates are pretty spot on, while others attest they are wildly inaccurate and should be ignored altogether.

Therefore, we’ve decided to investigate the research and settle the debate ourselves: Are treadmill calories accurate? Keep reading to find out! 

We will cover: 

  • Are Treadmill Calories Accurate?
  • How Accurate Are Treadmill Calories?
  • How Do Treadmills Calculate Calories?
  • What Can You Use Instead of Treadmill Calories?

Let’s get started! 

Treadmills.

Are Treadmill Calories Accurate?

According to Business Insider, calorie counters on cardio equipment are not all that accurate, particularly calories on treadmills and elliptical machines.

For example, a study published in 2018 compared the number of calories burned on an elliptical machine according to the calorie counter versus the actual number of calories burned according to indirect calorimetry (the gold standard for measuring energy expenditure).

The data revealed that some elliptical trainers overestimate the number of calories burned by as much as 130 calories over the course of a 30-minute workout. 

Although that may not sound like much, it can be both a significant percentage of the reported calories and a significant impact on your weight and diet results.

A person on a treadmill trying to figure out how accurate the data on the screen is.

For example, Harvard Health Publishing reports that 30 minutes of “general elliptical use” burns 270 calories for a 125-pound person, 324 calories for a 155-pound person, and 378 calories for a 185-pound person.

If you add 130 calories to each of these average energy expenditures, you get 400 calories for a 125-pound person, 454 calories for a 155-pound person, and 508 calories for a 185-pound person.

To put this increase in perspective, this caloric inflation leads to an overestimation of nearly 150% for a 125-pound person, 140% for a 155-pound person, and 130% for a 185-pound person. 

Furthermore, if you ate an extra 130 calories of food each day, thinking you had burned additional calories in your workout, you would gain over one pound of fat every month or close to 14 extra pounds in a year.

A treadmill screen.

How Accurate Are Treadmill Calories?

The primary reason that the treadmill calorie number is not necessarily accurate is that the algorithm the treadmill uses to determine the calories you burn running or walking doesn’t take into account all of the variables that influence your energy expenditure during exercise.

A treadmill typically only uses the body weight that you input, along with the speed and grade of the treadmill.

There are additional factors that can affect the number of calories you burn while running, including your age, sex, body composition, fitness level, and body size.

For example, one of the factors that most significantly affect the number of calories you burn doing any type of exercise is your body composition.

Muscle tissue is more metabolically active than fat tissue because muscles are actively contracting during exercise, so the muscle fibers are consuming oxygen to produce energy. 

On the other hand, body fat (adipose tissue) is fairly inert, so fat tissue is not really contributing to the calories you burn while exercising.

Therefore, the higher your body fat percentage, the lower the relative number of calories you burn while doing exercise.

Treadmills at a gym.

For example, if two runners both weigh 165 pounds (75 kg), but one runner has a body fat percentage of 30% while the other has 15% body fat, the runner with 15% body fat will burn more calories doing the same workout.

Because men tend to have more lean body mass than women and larger metabolically-active organs like the heart and liver, sex also impacts the number of calories you burn.

An often-forgotten factor that can also influence the energy cost of exercise is your fitness level and adaptation to the workout.

Consider the difference between two runners; each weighs 165 pounds. Both runners run the exact same workout on the treadmill: a 5-mile run at 7.5 mph at 1% grade.

The treadmill algorithm will spit out the exact same number of calories burned for each runner as they clip along during the workout, and at the completion of the workout, the treadmill calories between the two runners will be exactly the same.

However, the true caloric expenditure of the workouts could be quite different, depending on the fitness level of each of the runners.

If you are a habitual runner who does the same type of treadmill workout every day, your body will become more efficient at the workout, and you will gradually burn fewer calories.

Inexperienced runners who have poor running economy or for whom the workout is extremely taxing will burn more calories because the workout will be a much higher relative intensity of effort.

People running on treadmills.

Treadmills cannot take into account the efficiency of your stride. There’s a lot of freedom of movement on the running deck—you can have any type of running stride and still clip along the belt at the same pace.

Because there is a lot of individual variability in running gait patterns and the subsequent energy cost of running, treadmill calorie counts can be particularly inaccurate compared to a cardio machine that has a more defined path of movement like a stationary bike or a stair stepper.

Lastly, some treadmills do factor in your age, but many do not.

Age can impact the number of calories you burn running because our metabolic rate slows down as we get older, largely due to a loss of muscle mass (sarcopenia), as well as hormonal changes.

One important point to make note of is that if you use the handrails on a treadmill, the accuracy of the treadmill calories will be even worse. 

When you hold onto the handrails, you eliminate the upper body and core involvement of the exercise, making running or walking much easier. 

This, in turn, reduces the energy cost or calories burned on the treadmill.

However, the machine cannot detect whether or not you’re gripping the handrails, so the treadmill calories will grossly overestimate the number of calories burned if you are indeed holding on.

Of course, most people do not hold onto the handrails while they run on the treadmill, but it’s certainly something to be mindful of.

A person entering their data into a treadmill.

How Do Treadmills Calculate Calories?

Although it can vary based on the manufacturer, most treadmills calculate calories burned using a formula that pulls the metabolic cost of walking or running from the Compendium of Physical Activities. 

This is a vast catalog of energy expenditure data for various physical activities using Metabolic Equivalents, or METs.

A MET is a unit of energy expenditure or energy cost that is equal to 1 kcal per kilogram per hour. This baseline—1 MET—is basically the amount of energy you expend sitting quietly at rest. 

The energy expenditure or calories burned for any other activity can then be compared to this baseline. For example, if walking at 3.0 mph has a value of 3.5 METs, you burn 3.5 times as many calories walking per minute as you do sitting still.

While the METs values for running and walking at different speeds and inclines can give you a good ballpark idea of the number of calories you burn running or walking, these formulas do not take into consideration the personal factors previously discussed, such as your body composition, age, fitness level, etc.

For this reason, most health and fitness experts say that treadmill calories are typically a good 10 to 15% off in either direction.

As an example, if you run for 30 minutes, the treadmill might report that you burn 400 calories, but it’s realistic to assume that you actually burned anywhere from about 350-450 calories.

A person looking at their sport watch.

What Can You Use Instead of Treadmill Calories?

The best way to improve the accuracy of the treadmill calorie count is to properly fill out all of the data fields that the treadmill asks you.

For example, correctly enter your weight, height, and age if asked.

However, you can also utilize a fitness watch with a heart rate monitor to get a better estimate of the number of calories you burn on the treadmill.

With that said, some studies suggest these fitness monitors can be highly inaccurate, even more so than treadmill calorie estimates.

Therefore, it’s important to approach any sort of calorie expenditure data with some skepticism.

Especially if you’re trying to lose weight, assume that there’s an overestimation of some degree going on, so you might want to shave 15-20% of the calories burned off your final number and adjust your diet accordingly.

A watch that says 1192 calories burned.

For example, if the treadmill shows that you burned 500 calories, you can imagine that value might be padded by close to 100 calories. 

Thus, for the purposes of calculating your dietary needs, you can adjust the energy expenditure to 400 calories.

Remember that the calories you burn running are only one of the many benefits of exercise, so don’t be discouraged if you’re not burning as many calories as the treadmill shows. 

Instead, use that knowledge to inform your nutrition plan and focus on how great your body feels.

For an inside look at different types of exercise that burns calories, check out our guide to Which Workouts Burn the Most Fat?

A phone app with calories burned.
Photo of author
Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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