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Fitbit Charge 4 Review

Onwards and upwards, as the motto goes for any tech product, the Fitbit Charge 4 is the latest evolution of a Fitbit classic. The original launched back in 2014, and has evolved quite a bit over the last 6 years. As it stands, its predecessor (the Charge 3, reviewed here) is still available for sale and is by no means outdated, but there are some useful upgrades in the new model that will appeal to a good chunk of fitness tracker fans.

Quick Take


You’ll likely be quick to notice that the Charge 4 has a lot in common with its predecessor. It has the same dimensions, the same screen and strap (yes, straps are interchangeable), the same 7-day battery life, and at a ‘basic features’ level it’s almost the exact same device. Basically Fitbit’s design team went in and thought ‘what else can we cram into this little thing without reinventing it?’ and this is where we ended up.


NFC Payment
Compact Design


Greyscale OLED Screen

What To Know About the Charge 4


There are three big wins that came with this upgrade, but the hero of the pack is on-board GPS. Being able to wear a tracker as compact as the Charge 4 without having your phone as a GPS source is a big win for runners and cyclists, among others, though it’s worth noting that this feature comes at a cost. With GPS on, battery life burns down quickly, with Fitbit claiming 5 hours. Alongside this new feature, NFC payment is now a standard feature on the Charge 4 (was introduced on Charge 3 Special Editions), as is Spotify control. There still isn’t an option for on-board music, but given the device’s compact nature we aren’t surprised here.


Other Fitbit Charge 4 Key Features and Specs:

  • Water resistant to 50 meters
  • Touchscreen
  • Blood oxygen monitoring (VO2 Max)
  • 7 day battery life (depending on usage)
  • 24/7 heart rate tracking
  • All-day activity tracking — steps, floors climbed, active minutes, & more
  • Detailed sleep cycle tracking
  • 15+ goal-based exercise modes
  • Automatic exercise recognition
  • Smartphone notifications


As the charge series continues to evolve, we’re impressed to see that Fitbit didn’t up the sticker price on the new feature-rich model. Full retail is $169.99 (though it can and will go on sale). Because the Charge 3 is still on the market for now, Fitbit has lowered the price of the older model until that stock clears out. Depending on current offers, the gap between the Charge 3 and Charge 4 is between $50 and $70, though we suspect many will still be willing to pay more for the now available phone-free experience.




There really isn’t a ton to talk about here, as the Charge 4 is identical to its predecessor. Its screen is the same size and resolution, its straps, its inductive button; the list goes on but fundamentally all of the changes to the Charge 4 are internal, other than its available strap colors. When the Charge 3 launched we were OK with its greyscale OLED display, however as more brands turn to full color this becomes a small strike against the new release. The contrast of the Charge 4’s display could use a bit of work, but on the other hand there’s likely good reason for the display choice. Especially with features like GPS, battery consumption is a major consideration, and this type of display helps Fitbit in maintaining adequate battery life without increasing device size.


Sensors & Components


The Charge 4 features all the fixings for solid fitness tracking. That includes:


  • Optical heart rate monitor
  • Accelerometer
  • Gyroscope
  • Altimeter
  • GPS
  • Relative SpO2 sensor


Since our last coverage of the charge series, Fitbit has finally unlocked blood oxygen saturation monitoring as calculated by its relative SpO2 sensor. A means of monitoring blood oxygen levels, this not only adds a metric to sleep monitoring, but can help provide an indication of breathing issues like sleep apnea. This might seem odd for a fitness tracker, however sleep apnea is a condition that typically requires a sleep clinic to diagnose, and it’s also shockingly common. Approximately 26% of Americans have it, and while wearing the Charge 4 is not a direct substitute for diagnosis, it can definitely help flag blood oxygen saturation as a point of concern to raise to your family doctor.




Aside from GPS being able to run independently of your phone, there are a few additional improvements found with the Charge 4. Activity tracking is still on point, including automatic workout detection for running, swimming, cycling, and more. In automatic mode you won’t be able to see GPS mapping—that requires starting your specific workout on the device.


Fitbit is also leveraging heart rate data to a greater extent with the metrics delivered by the Charge 4. A new stat dubbed Active Zone Minutes can be seen, and this category is focused on being an additional mobility motivator. The American Heart Association recommends a minimum of 150 minutes of moderate intensity activity each week, so Fitbit has set this as a target. Every minute logged in the fat burning zone counts as an active zone minute, whereas every minute in peak/cardio heart rate zone counts for two active minutes.


Fitbit also maintains its insightful sleep tracking with the Charge 4, alongside having added the aforementioned blood oxygen saturation monitoring. Fitbit has put a lot into developing and improving their sleep tracking capabilities. Sleep is tremendously important when we’re talking about overall health, so having an idea about your habits is a smart way to ensure you’re working toward a better you. Part of the benefit of Fitbit maintaining a compact profile on the Charge 4 is that it remains relatively comfortable to sleep with when compared to bulkier trackers and smart watches.


In the sleep tracking part of the app, you can set goals and bedtime/wake-up times, as well as continue to see trends and improvements over time. No device is perfect in terms of accuracy, but Fitbit seems to be one of the leaders in that respect. While it can be slightly off during the fall asleep/wake up stages, this is largely due to the changes in our bodies as we start to drift off and as we begin the torturous process of waking up in the morning.



There’s a lot to consider here, but if your focus is on function over flash the Charge 4 is an easy choice. Packing in all of these features into a compact device is never easy, and if you’re more interested in colorful watch faces than useful training and health metrics, we’d recommend looking elsewhere. The additions of GPS and NFC payment alone make up the Charge 3’s only real shortcomings, and especially during the ongoing COVID-19 pandemic, having touchless payment is a perk that more folks should be adopting.

Rating: 92%


Product Type

Fitness Activity Tracker

Brand/Model Series

Fitbit Charge 4

Overall Rating

92 %

Phone Control


Removable Band


Fitness Tracker Type


Number of Available Colors




Type Of Display

Backlit OLED



Sleep Tracking


Steps Tracking


Calories Tracking


Bluetooth Enabled


Heart Rate Monitor


Water Resistance Rating


Max Battery Life

168 hrs







On-board music storage


NFC Touchless Payment


View Full Specifications