How many steps did you take today? Are you sure? How do you know?
If you're one of the many people wearing a fitness band or smartwatch to count your steps, you may not be aware of one inescapable fact: they're lying. Just because they tell you that you have reached your daily goal does not mean that you actually took so many steps. The sad truth is that these devices can under-count or over-count the number of steps you can take in a day. In fact, your counts can vary greatly depending on the brand you are using.
Some of the reasons depend on how they work. Today's fitness tapes use multi-axis inertial sensors, called accelerometers, to detect when the device is moving. Some also use gyroscopes to determine direction and rotation. Because these sensors generate so much data that needs to be sifted and interpreted by the device's controller, the results can often be misinterpreted and reported incorrectly. In other words, what you see does not necessarily have to be what you left.
There can be several reasons for this.
When your fitness tape interprets the data from its motion sensors, it should ignore movements that are not associated with walking. However, it is not always successful. For example, if you hit your nails with a hammer, you may experience vibrations that are close enough to make movements that interpret the data as faulty.
Finer movements can also cause errors. Wash your hands, prepare your food, pet your cat or use a computer mouse. This can also cause steps to be registered by your device. If you use vibrating devices, such as For example, an orbital sander that you use for a woodworking project can cause your tracker to log hundreds of steps in a matter of minutes.
However, it is not just deliberate movements that can be misinterpreted. Vibrations that affect all or part of your body can also result in inaccurate step counts. For example, driving in a car, bus, train or subway can cause movements that are interpreted as steps. You can add hundreds of steps while driving your car for an hour or less.
For example, driving in an elevator can be registered as climbing stairs. Changes in air pressure when driving in a car or other moving vehicle may also affect the count as well as entering and leaving skyscrapers with a different air pressure than the outside air pressure. Even fast weather changes can be registered as climbing floors.
How To Keep Your Numbers Accurate
Tracker's are not perfect when it comes to counting steps or climbed flights. However, you do not need perfect accuracy to determine if you have taken much more or fewer steps today than yesterday. You can take various measures to ensure that you get the most accurate readings possible.
The most important first step (so to speak) to make sure your device is as accurate as possible is to read the manual. Carefully follow the manufacturer's instructions when setting up and using the device. Ensuring that you are using the tracker correctly will make it more likely that you will do an accurate count.
Use your non-dominant hand.
Many trackers ask you if you're wearing the device on your dominant or non-dominant hand. Your dominant hand is likely to be more active – whether you are working with a tool or stirring a pot – leaving more opportunities for mistakes. Even if the instructions of your tracker do not cover this, you should wear your device against your non-determining hand.
Make sure that you wear the device so that it sits firmly against your wrist. Some people do not like a tight fit for their watch or bracelet, but if your fitness belt jumps around your wrist, you're likely to get wrong increments. (A loose fit may also cause heart rate sensors and other features to malfunction.)
Keep track of your inactive times while sitting or doing other activities that are not about walking. You can then deduct these incorrect steps from the total score of your day. This also gives you an indication of how many of these misinterpreted steps occur on a typical day. You can also remove the tracker before you start activities that you know will cause false results, such as: When using a grinder or playing a musical instrument. These do not affect editorial content, although Vox Media may earn commissions on products purchased through affiliate links. For more information, see of our Ethics Policy .