It might not be necessary to spend money on a fitness-tracking device if you already own a working smartphone.
According to a new study from the University of Pennsylvania School of Medicine, free smartphone apps can be about as accurate at measuring your steps as popular wearable fitness devices, many of which cost around $100.
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That said, it’s worth keeping in mind that the study observed only 14 participants — and only a handful of devices and apps, when there are dozens and dozens available to consumers.
Companies sold millions of fitness trackers in 2014, and they’re expected to sell millions more this year, even though the market for them is contracting in response to the arrival of smartwatches. Two-thirds of adult Americans already have smartphones.
