Which Fitness Wearable Is The Most Accurate?

It’s becoming increasingly difficult to pick the best fitness tracker. Until recently, only one or two brands offered advanced features like heart-rate monitoring. Now it seems like most of the products out there not only do the same things but even look the same. The only real differentiator—and the one that really matters—is accuracy. But how can you cut through the marketing hype and find out which of today’s trackers will measure your activity most accurately? Turns out, the answer isn’t so straightforward—yet—but it starts with three important words. (And no, they’re not the same ones your girlfriend has been waiting to hear.)

“We’ve been acquired!”

That’s the message you’ll be greeted with if you head over to the official website of BodyMedia, the makers of the Core activity tracker.

Why should you care about the acquisition of a brand you’ve probably never heard of? Well, it has everything to do with a recent study, the results of which were published in the latest edition of the journal Medicine & Science in Sports & Exercise.

In a trial designed to test the accuracy of four popular activity trackers—the Fitbit Flex, Nike+ FuelBand SE, Jawbone UP, and Misfit Shine—researchers at Iowa State University’s Department of Kinesiology collected data from 56 study participants in real-life conditions ranging from working at a computer or reading a book to performing aerobic or resistance exercise. At the end of the trial, the researchers found that the most accurate fitness tracker you can buy right now is… none of them.

As it turns out, there were two additional trackers that the study authors included in their experiment—the BodyMedia Core and the Actigraph GT3X. You may not have heard of either, probably because they’re used primarily in medical research, and neither is widely marketed to consumers. They probably wouldn’t do very well, anyway. The BodyMedia Core, while offering an impressive array of useful features like galvanic skin response (i.e. perspiration), doesn’t have a display, and you have to pay a monthly fee to access your data. The Actigraph GT3X, meanwhile, looks like something that was ripped off the top of a firetruck. That said, both outperformed all four of the popular consumer products.

Here’s how all six devices performed when tested in three categories (aerobic, sedentary, and resistance activity), starting with the overall ranking. The percentages denote rate of error.


  • BodyMedia Core 15.3 percent
  • Actigraph GT3X+ 16.7 percent
  • Fitbit Flex 16.8 percent
  • Nike+ FuelBand SE 17.1 percent
  • Jawbone UP 18.2 percent
  • Misfit Shine 30.4 percent


  • BodyMedia Core 17.2 percent
  • Nike+ FuelBand SE 18.5 percent
  • Actigraph GT3X+ 22.1 percent
  • Jawbone UP 30.0 percent
  • Fitbit Flex 34.7 percent
  • Misfit Shine 60.1 percent


  • BodyMedia Core 15.7 percent
  • Misfit Shine 18.2 percent
  • Nike+ FuelBand SE 20.0 percent
  • Fitbit Flex 29.4 percent
  • Jawbone UP 29.4 percent
  • Actigraph GT3X+ 45.2 percent


  • Nike+ FuelBand SE 20.0 percent
  • BodyMedia Core 29.2 percent
  • Fitbit Flex 31.6 percent
  • Misfit Shine 36.8 percent
  • Actigraph GT3X+ 45.2 percent
  • Jawbone UP 52.6 percent

Now, back to those three critical words. Specifically, the announcement that BodyMedia, the manufacturer of the highly sophisticated Core, which now holds the title of Most Accurate Fitness Tracker, is now a fully owned subsidiary of, wait for it—Jawbone.

So, there’s your answer. Right now, as far as consumer products go, Fitbit is your best bet for accuracy. But very soon that will likely change as fashion-forward Jawbone begins incorporating technology from its shiny new toy.

Flex while you can, Fitbit; Jawbone is about to be up, up, and away.

Photo: Chris Ford


6 thoughts on “Which Fitness Wearable Is The Most Accurate?

    1. Yup. If you really want one, Amazon still has them. But the monthly data support probably won’t last for long, if it’s still running at all.


  1. This actually has been around for a very long time. It was accurate 5 years ago when I wore it under the name BodyBugg. It became pretty popular during the first few seasons of the Biggest Loser as all of the contestants wore them.

    Liked by 1 person

    1. Exactly right. Amazing that it’s been around for that long and yet nobody has caught up. I guess acquisition is easier than innovation.


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