--- title: Fitness Bands Ranked By Accuracy description: Fitness trackers like Jawbone Up and Fitbit are growing in popularity, but scientists wonder how accurate they really are. Researchers from Iowa State University compared eight popular brands canonical: https://time.com/2857434/find-out-how-accurate-your-trendy-fitness-monitor-is/ author: Alexandra Sifferlin article:opinion: false article:content_tier: free article:published_time: 2014-06-11T17:10:37.000Z article:modified_time: 2026-02-21T08:21:01.118Z article:section: Health og:title: Find Out How Accurate Your Trendy Fitness Monitor Is og:description: Scientists compared the accuracy of eight popular fitness bands og:url: https://time.com/2857434/find-out-how-accurate-your-trendy-fitness-monitor-is/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt5ff42b7551b48bdc/69869713e8524b2d4860366b/6ct0.jpg?branch=production&width=3840&quality=75&auto=webp&crop=16:9 og:image:width: 1200 og:image:height: 675 og:image:alt: 6CT0 og:type: article twitter:card: summary_large_image twitter:title: Find Out How Accurate Your Trendy Fitness Monitor Is twitter:description: Scientists compared the accuracy of eight popular fitness bands twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt5ff42b7551b48bdc/69869713e8524b2d4860366b/6ct0.jpg?branch=production&width=3840&quality=75&auto=webp&crop=16:9 ---  # Find Out How Accurate Your Trendy Fitness Monitor Is by [Alexandra Sifferlin](https://time.com/author/alexandra-sifferlin/) ## Alexandra Sifferlin Jun 11, 2014 5:10 PM UTC  Photo by Bob Elbert by [Alexandra Sifferlin](https://time.com/author/alexandra-sifferlin/) ## Alexandra Sifferlin Jun 11, 2014 5:10 PM UTC Activity monitors used to be tools that only scientists used during research, but the fitness-tracking industry, which is projected by analysts to be a [$19 billion business by 2018](http://www.juniperresearch.com/viewpressrelease.php?pr=405). But how accurate are they really? In a [new study](http://www.news.iastate.edu/news/2014/06/09/fitnessbands) from Iowa State University published in the journal [_Medicine & Science In Sports and Exercise_,](http://journals.lww.com/acsm-msse/Abstract/publishahead/Validity%5Fof%5FConsumer%5FBased%5FPhysical%5FActivity.98139.aspx) researchers assessed how well they actually work. To test the products, 30 men and 30 women wore eight popular monitors during a 69-minute workout that included exercises like Wii tennis, running, and playing basketball. They also wore a medical-grade metabolic analyzer for comparison. The researchers found that some devices were pretty accurate, with estimates within 10 to 15% of precise calorie burn. Here’s their list, ranked from most to least accurate: 1\. **BodyMedia FIT** performed best with a 9.3% error rating. The researchers say this device has a similar accuracy to devices used in research. That’s probably because 10 years prior to releasing a consumer product, BodyMedia was [developing](http://healthland.time.com/2013/03/14/south-by-southwest-sxsw-will-collecting-data-on-your-body-make-you-healthier/) products specifically for the medical research industry. 2\. **Fitbit Zip** had a 10.1% error rating 3\. **Fitbit One** had a 10.4% error rating 4\. **Jawbone Up** had 12.2% error rating 5\. **Actigraph** had a 12.6% error rating 6\. **Directlife** had a 12.8% error rating 7\. **Nike Fuel Band** had a 13% error rating 8\. **Basis Band** had a 23.5% error rating You can read more about the researchers’ work, [here](http://www.news.iastate.edu/news/2014/06/09/fitnessbands). ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/2857434/find-out-how-accurate-your-trendy-fitness-monitor-is/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/2857434/find-out-how-accurate-your-trendy-fitness-monitor-is/"},"headline":"Find Out How Accurate Your Trendy Fitness Monitor Is","datePublished":"2014-06-11T17:10:37.000Z","dateModified":"2026-02-21T08:21:01.118Z","description":"Fitness trackers like Jawbone Up and Fitbit are growing in popularity, but scientists wonder how accurate they really are. 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