Fitbit Charge 4 Black Advanced Fitness Tracker

I had a charge HR fitbit from 2016 until 2022, which worked perfectly. After a few years the band (not replaceable) came off, and I re-glued it, device still worked perfectly. In 2022 I decided to upgrade to the Charge 4 due to SpO2, sleep stage, etc. monitoring. The Charge 4 has worked perfectly since then. My only complaint is the band, which is stiff and not too comfortable (I wear it 24/7/365). That was solved by use of a fabric velcro wrap band (AVOD, reviewed elsewhere). Since I got that band I absolutely love the Charge 4. I bought more as backups, but they haven't been needed. Gave one to my wife, who likewise likes it. There are some caveats about accuracy, which I'll discuss in a minute, but I find them not to be an issue as long as you're aware of them. My issue is Google, which bought Fitbit. Before that, everything worked like clockwork. Give username, password, log into Fitbit, use app, stay logged in for months, easy-peasy. But for a couple of months Google is telling me that as of 2/2/2026 I can no longer use the app unless I switch the account to Google. No more email login. OK, pain in the butt, but OK. EXCEPT: The link Google gives DOES NOT WORK. It tells me my email is "already in use for a different device" so I can't move it. [the Charge, maybe? Who knows. They give zero details, and zero ways to remediate.] They also won't let me move it to a new email. Zero stars for the Google experience is too generous. My "backup plan" is to use one of the brand new Charge 4s and try to set it up on Google when they shut off "my" three year old one. Based on the experience so far, I give that about a 5% chance of working, but if it does, I'll try to update the review. [Or if a miracle happens and I can get the current one switched to Google.] So: Charge 4, top notch except limitations below. Google: For such an advanced outfit with so many brilliant people and such great AI and search, their customer interface on this SUCKS. Accuracy limitations/caveats on Charge 4. Basically, I have found it to be extremely accurate, but there are limitations. When you first stand up and walk, it misses the first few steps...several more than the Charge missed. Not really an issue. I might miss 50 steps a day that way. If your only "walking" is moving from a couch to an electric wheelchair, you might lose a good fraction of your few steps. If you take walks, it is with 1% of GPS distance. And the step count is extremely accurate. If I manually count steps walking around the house, it's within 1 or 2% of the manual count. A+ on that. [Likewise, if I run on a treadmill, it agrees with the treadmill within 1-2%] It does NOT, in general, for me, respond to wrist motions as "steps" although you can learn to move your wrist in such a way as to make it sometimes count a "step". I find that a non-issue. If I get a dozen fake steps a day from wrist motion, it balances the steps I miss when first standing up/walking. A+ overall on distance, steps. Pu;se rate: There is an issue with pulse rate. The issue is that when it changes dramatically (say from walking to running) the pulse registered is inaccurate. If I go from walking around the house to running up and down stairs, for example, the Charge 4 will tend to read about 20 beats/min high. It will record random spikes of 50 beats too high, so the "max" pulse during exercise needs to be taken with a grain of salt (pulse rate based on comparison to pulse oximeter or ECG heart rate monitor). But, if I sit in a chair, or walk at a steady pace, the fitbit, pulse oximeter, and the ECG all agree (again, 1-2%). I sleep with a pulse oximeter every night, the Charge 4 is within one or two beats of the pulse/ox every night. It averages a fraction of a beat different. A+ for accuracy on pulse WHEN you are in a steady state condition, particularly resting. So: Don't trust the instantaneous pulse readout IF you have just changed level of exertion. Don't trust the spikes. Otherwise, pretty good. Calories: Fitbit Calories are based on pulse rate, so the errors in pulse rate tend to overstate calories burned. I keep a record of calories based on distance walked, run, basal metabolism, etc. and the Charge 4 tends to overstate daily calorie burn by 20% or so, for me. You could determine how much it is for you, and if you like, adjust the number. For a given exercise session, the numbers are roughly credible say 10-15% of independent measurement, sometimes right on the independent measurement. That's all close enough for me. YMMV. Sleep: I had a professional sleep study under medical supervision. I wore my pulse/ox and the Charge 4 at the same time. As mentioned, the Charge 4 agrees with my pulse ox for pulse rate overnight, and is pretty close (tends to be 1-2% low) on SpO2. My pulse/ox (Sleepu) and Charge 4 likewise agreed with average pulse and SpO2 from the professional study (2% ish difference). Remarkably, I thought, the SLEEP STAGE durations reported by the Charge 4 were close (to my mind) to the professional device, which has far more input data. The Charge 4 underestimated Deep Sleep by 25% or so, but showed each stage at the time the professional unit showed it. I considered that to be pretty amazing. Overall: Fabulous for a cheap device with such limited input. Will be sorry to lose it to Google's messing about.

I work in a hospital and have access to a ton of devices that accurately measure heart rate, in addition to simply counting my HR with a stopwatch. Upon comparison Charge4 is off by 15 to 20% about most of the time and has inexpiable spikes that claim my HR is 200% or more higher than it actually is that last minutes at a time. The pedometer picks up normal hand movements as steps. After spending 6 hours on the couch and only getting up 3 times it claims I have gone up 9 flights of stairs and walked over 7000 steps equaling over 3 miles. Even rotating your wrist to get the display to turn on can sometime count up multiple steps. The health metrics in the app are largely based upon heart rate and steps taken. When both of these are wildly inaccurate it cannot give you a clear picture of even the number of calories you have burned in a day much less anything more in depth. The sleep metrics are a cute idea but largely anecdotal and not really useful as the advice they foster from the app are the exact same suggestions you would tell every single person in the world regardless of their specifics as to what will give them the best sleep. Keep a regular bedtime, don't work out right before bedtime, etc... The never-on-when-you-need-it display that is invisible in sunlight is not a big selling point either. And the cherry on top? Tech support's only suggestion was to try restarting the watch followed by absolute silence and zero help or suggestions. This thing fails spectacularly.

I love Fitbits- have had two now and like the functionality of the app. I didn’t use mine for texting but was happy with the heart rate monitoring and step counting. However, after about 8 months, the plastic pegs that hold the bands on snapped off. This is the second time it has happened. First time, I bought the Fitbit at Costco and they gave me a full refund. I decided to take a leap of faith and order the same one here on Amazon (Costco was out of this version) and I liked how slender it was. Figured it was a fluke the first time, but it happened again. I contacted Fitbit customer service through the Fitbit app, and they replaced the part with a new watch face in a matter of a couple of days. I’m so happy with the quality and speed of the service and the watch face seems improved to the last one. Happy to still use my Fitbit!

So features wise, this was an awesome Fitbit. Note the “was”… I’ve had two. There is a design flaw in how the bands connect to the bit. The first one I bought lasted quite a while (maybe 3years?) and finally the plastic “anchor” that you attach the band two sheered off at the base, making it impossible to replace, glue, etc and thus you can’t attach the band. The second fitbit lasted less than two months. Same break. Horribly disappointing. I loved this product but I can’t afford to spend that much money for it to break I a critical way. I have 2 working charge 4 bits I can’t use. Wish they’d thought about the design issue.

The version 4 of the fitbit is hard to find. I ordered one but it arrived with a dead display. But the vendor replaced it quickly. The replacement works perfectly. This was a replacement for a version 4 that had been in use for a few years before it died and I didn't want to move to a newer version.

I have had a fitbit Charge 4 for years. I liked the simplicity and ease of use, as well as the 7 day battery life. So, I took a chance and ordered a new Charge 4 even though it is several model years old. Big mistake! Initially, the new charge 4 synched to the Fitbit App and everything was fine. But then, after a week, it would lock up and never finish synching. I restarted the app, re-paired the device and finally did a hard reboot while charging. It worked again for 2 days, then suddenly stopped recording my steps. I did another hard reboot and it worked for 1.5 days. Then, it stopped recording steps again and the heart monitor stopped working. And then many other things started displaying bad information. At that point, I gave up and returned the defective device. I'll be moving to an Apple Watch SE. So sad as I loved my Charge 4 and really hoped it was a device that I could keep using for the future.

My second one. Works perfectly. Everything I want it provides.

The Fitbit Charge series is a favorite among fitness watches. Why? It's the form factor (shape). For me and other repeat buyers, a round shape is "old timey." A second powerful reason is that many of us LIKE the e-paper display - crisp white or gray-scale characters create a uniquely attractive presentation. Dense color displays are "eye candy" and a turn-off to many. It's unfortunate that it appears the Charge 4 is the last of the e-paper displays - a shame and, to me, a marketing decision which I hope Fitbit's parent company reconsiders. df