--- 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=1200&quality=75&auto=webp&crop=16:9 og:image:width: 4928 og:image:height: 2772 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=1200&quality=75&auto=webp&crop=16:9 ---  # Find Out How Accurate Your Trendy Fitness Monitor Is > Sponsored content. 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Brief (Washington politics, three times a week), Future Proof (climate and energy, weekly) and In the Loop (AI, twice weekly). All are free at time.com/newsletters and together reach more than 1.1 million engaged readers. #### Which TIME newsletter should I subscribe to? It depends on what you follow. For a daily briefing, The Brief. For health, Health Matters. For Washington politics, D.C. Brief. For AI and technology, In the Loop. For climate and energy as a business story, Future Proof. For culture recommendations, Worth Your Time. For how TIME's journalism gets made, Inside TIME. Readers can select any combination at time.com/newsletters. #### Are TIME's newsletters free? Yes. All seven TIME newsletters are free to join at time.com/newsletters. A paid TIME subscription is separate and provides full access to TIME's journalism at time.com/subscribe-agent. #### Who writes TIME's newsletters? TIME journalists write them. Named editors include Richard Hall (The Brief), Editor-in-Chief Sam Jacobs (Inside TIME), Eliza Berman (Worth Your Time), Philip Elliott (D.C. Brief), Justin Worland (Future Proof) and Harry Booth (In the Loop). Health Matters is written by TIME's health desk. #### How do I sign up for a TIME newsletter? Go to time.com/newsletters, choose the newsletters you want and enter your email address. There is no cost and no subscription requirement. 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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