How Accurate *Are* Step Counters, Anyway?

by Carolyn de Lorenzo

Fitness trackers and wearables are super handy for helping to monitor our exercise habits, especially when we're trying to get more active time in. And if you use step counting apps, you know how helpful they can be for keeping track of your fitness goals. But how accurate is your step counting app, actually? As it turns out, the accuracy of your phone's step-counting app might not be super on point — but that might actually be a good thing.

According to a study published last year in the Journal of Sports Sciences, your iPhone’s step count is probably not the best pedometer ever, but what’s great about that is, you’re likely walking more steps than your phone is accurately tallying. Tonic reports that researchers at the University of British Columbia devised a two-part study — one conducted under lab conditions, and the other in a real-world setting — to compare iPhone’s Health app with a wearable waist-worn pedometer built solely for the purpose of step counting. They found that the iPhone step counter underestimated steps walked by about 1,340 steps during a typical day. Meaning that, if your iPhone’s step counter says that you trekked the recommended 10,000 steps per day, you probably did about 20 percent more than that. Which is not the worst news in the world, right?


The International Business Times further notes that, in the study involving 33 participants, two iPhones — one personal and one shared — were used per participant in order to asses device accuracy and possible user error. Researchers found that iPhone step counting apps were more accurate when participants walked at higher speeds, but less so at slower speeds; while the shared devices were a bit more accurate than the personal phones. Tonic reports that some user error was reported — like when participants forgot to bring their phones along on trips to the restroom or to get water, for instance. And slower-paced walking throughout the day during certain tasks could also yield less app accuracy, according to the previous lab reports.

The study implies that, while your iPhone’s step counter is probably not perfectly accurate, it can still give you a fair sense of how much walking you’re doing each day. According to Tonic, study author Guy Faulkner said in a press release that, for the most accurate reading, “You just have to have [your phone] on you at all times."

It's also worth noting that, for this study, researchers didn't observe other phones' step counting apps, or other fitness trackers like the Apple watch, Fitbit, or other wearables. According to The Berkeley Science Review, fitness trackers are still pretty new, and research is limited in terms of how well they stack up in terms of accuracy. And while your iPhone step count might have some shortcomings, Fitbits hold up pretty well under scrutiny, according to Berkeley — at least as far as step count trackers go.

Ashley Batz/Bustle

But, at the end of the day, it's important to remember why fitness trackers are useful in the first place. While taking 10,000 steps per day is a great number to shoot for, USA Today notes that the point of setting that goal is to simply sit less and exercise more, in order to improve your health outcomes long term, per the Centers for Disease Control (CDC). Obsessing over the literal amount of steps you take per day doesn't give you that much useful information about your health, except for the fact that you walked this much; the more useful fact is that you walked that much, at all.

Whatever step counting app you choose, it will probably work fine to help you reach your broader fitness goals, but it's important to remember that the literal number is less significant than how you feel at the end of the day, whether you walked 5,000, 10,000, or 15,000 steps. And you can enjoy the satisfaction of knowing that, if you’re iPhone step counter says that you hit 10,000 steps in a given day, you probably exceeded your walking goal by quite a lot — and that’s definitely a good feeling.