How accurate are Fitbit trackers?

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Fitbit is dedicated to developing the most accurate activity trackers on the market. 

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Why does my step count differ depending on where the tracker is worn?

With wrist-based trackers, if you move your body a lot and not your arms (or vice versa), you may see a slight difference in step count than you would see if wearing a clip-based tracker on your torso. 

If you have your Flex 2 in a loose fitting accessory such as a bangle or pendant, you can expect greater variation in your stats. During workouts we recommend wearing the classic elastomer band and ensuring that it fits securely but isn't too tight. For more tips see How do I wear my tracker?

Why do I get extra steps sometimes?

Fitbit trackers have a finely tuned algorithm for step counting. The algorithm is designed to look for intensity and motion patterns that are most indicative of people walking and running.  When working at a desk, cooking, or doing other arm movements, a tracker on your wrist can pick up some extra steps if it thinks you're walking. Many of these situations—such as working or cooking—do include a few steps in-between stationary periods so the tracker tries to give you credit for those steps. For the vast majority of customers, the amount of stray steps accumulated is negligible when compared to the entire day. For a more technical explanation, see How does my tracker count steps?

Why do I get steps when I'm riding a bike?

On bumpy trails it's possible that your tracker will register steps but these should be negligible in your overall stats. If you have a tracker with multisport mode, make sure you choose the Bike exercise before starting your workout. If you're relying on SmartTrack to automatically detect your bike ride, make sure the Outdoor Bike exercise is on. (In the app, tap the exercise title and then tap the gear icon in the top right.) If your tracker doesn't offer multisport mode or SmartTrack, we recommend logging your bike ride manually to get the best calorie burn estimation. For more information see How do I track my exercise and activities with Fitbit?

Why do I get extra floors sometimes?

If your tracker measures floors, it detects floors using an altimeter, which is a sensor that calculates altitude based on atmospheric pressure. Though your tracker is designed to look for pressure changes based on elevation gains, pressure changes due to other causes—such as a gust of wind, a weather change, or opening a door—can occasionally cause your tracker to register an extra floor or two. Another factor is floor height. Your tracker registers one floor when you’ve gone up about ten feet, which is the average between residential and commercial floor heights. If you climb long staircases you may find that the tracker’s floor count doesn’t match how many floors you’ve gone up since the staircase was taller than ten feet.

Will my tracker count steps if my arms aren't moving?

If you're doing something like pushing a stroller or shopping cart, your wrist-based tracker will count your steps but the total may be slightly lower than usual.

Will my tracker pick up steps when I’m in the car or riding a vehicle somewhere?

Your tracker has been tested against driving, buses, trains, and other public transportation and should not give you extra steps when you’re traveling under normal conditions. On bumpy roads or in a car with a stiff transmission you may get extra steps. Though a few extra steps won't affect your trends, if it bothers you it's possible to log a Driving activity and remove the steps from your account totals. For more information see How do I delete data?

Does the wrist I wear it on affect accuracy?

For wrist-based trackers, it's important to specify whether you wear the tracker on your dominant or non-dominant wrist:
  • The dominant wrist setting decreases the sensitivity of step counting and should reduce any over counting of steps when your body is not moving.
  • The non-dominant wrist setting increases the sensitivity of step counting and should reduce any under counting of steps. Non-dominant is the default.
In addition to dominance (right or left), Fitbit Alta and Alta HR also need to know which wrist you prefer to wear the tracker on. Tracker location helps orient the screen correctly in addition to adjusting the sensitivity of step detection.

To change your settings, in the Fitbit app go to Account tab and choose your tracker at the top of the screen.

What can I do if my step count seems inaccurate?

If you feel that your step count and distance are inaccurate, first make sure the wrist placement settings are correct. Next, double check that you entered your height correctly. Since we use height to estimate your walking and running stride lengths, you may want to measure and manually adjust these values if your legs are longer or shorter than average. For more information, see How do I measure and adjust my stride length?

Sometimes, when you start walking you may notice that your steps may not update on your tracker right away. After about 10-15 continuous steps, you'll notice the steps catch up and start updating in real-time with each step you take.

​To help with the accuracy of your Zip or One tracker, ensure that you’re wearing the clip-based tracker in the correct location. For more information on how best to wear any tracker, see How do I wear my tracker?

If my tracker measures heart rate or GPS how reliable is this data?

For these topics, see What should I know about my heart rate data? and How accurate is GPS?
Last updated: May 19, 2017
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