An Apple Watch Series 6 smartwatch with a yellow band on a user's wrist

All things considered, the Apple Watch Series 6 is slightly better than the Series 5 model released a year ago.

The new watch comes equipped with a blood oxygen sensor. It's optimized for the sleep-tracking feature Apple introduced in the recent WatchOS software update. And when it comes to the basics—heart-rate tracking and step counting—the model proved to be just a bit more accurate than the Series 5.

None of that screams must-have gadget. But it does lift the Series 6 to the top of Consumer Reports' very tight smartwatch ratings.

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The Apple Watch 6 starts at $400 for a 40-mm GPS-only model with an aluminum finish. The 44-mm model will run you $30 more. And cellular-capable models start at $500.

Are the model's new offerings worth that kind of money? That's a good question, especially given my experience with a temperamental blood oxygen sensor and an ill-fitting Solo Loop band.

In the end, a lot of people might crunch the numbers and find that their needs are met by the new Apple Watch SE, which has less in the way of bells and whistles but performed great in our testing. A GPS-only, 40-mm version of that watch costs a more modest $280.

To help you decide between the two options, here's a closer look at our findings on the Series 6.

Sleep Tracking

Sleep tracking, as a concept, isn't a new thing. Fitbit smartwatches and fitness trackers have been outfitted with the required tech for years. But the feature does bring Apple Watch wearers up to speed with the general public in the popular pursuit of better sleep habits.

To be clear, the sleep-tracking functions are actually coded into the watchOS 7 update that can be installed on any Apple watch dating back to the Series 3. But because of the lengthy battery life needed to power them, the Series 6 is best suited for their use. It has a quick-charging feature that helps you top off the battery before drifting to sleep.

The blood oxygen sensor helps, too. It works together with Apple’s Sleep app to shed light on your respiratory health and slumber quality, feeding data to the Apple Health app on your iPhone.

In addition to collecting such data, Apple's Sleep app allows you to set hourly sleep goals and bedtime reminders that help you wind down in the evening, giving you the option to turn off nonessential notifications and dim your display.

Instead of being jolted awake in the morning by a piercing audible alarm, you can set your watch to gently coax you from sleep with a light buzzing on your wrist. Better yet, it doesn’t interrupt the slumber of anyone nearby.

After a couple of nights of tracking, I can say the watch did a pretty good job at logging my sleep. It figured out when I went to bed each night and got up each morning. And it even recognized the hour of sleep I missed one Saturday when I crawled out of bed—temporarily—to help my husband get our son ready for an early morning hockey game.

Though CR didn't formally test Apple's sleep-tracking technology—that would require a research-grade sleep lab—the feature made it painfully clear that I was falling significantly short of my 8-hours-a-night sleep goal. And, I guess, just knowing that is a win.

The sleep-tracking app also allows you to put the watch in “do not disturb” mode and temporarily turn off notifications, which I highly recommend doing. Even if you mute the sound, the vibration of a silent alert can be enough to wake many people up in the middle of the night. 

Blood Oxygen Monitoring

Images showing the Apple Watch Series 6's blood oxygen results and an error message.
The Apple Watch Series 6's blood oxygen app can be tricky to use.
Photo: Bree Fowler

With many people turning to health-tracking devices during the pandemic, the blood oxygen sensor on the Series 6 sounds like a compelling option.

But it wasn’t as effective as I had hoped.

In fact, other than noting that most healthy people have blood oxygen percentages of 95 percent or higher, Apple doesn’t really give much in the way of advice on what to do with the data.

If you’re a hard-core athlete, you can use the readings for insight into how your workouts affect your oxygen consumption. And if you live at a high altitude, where the air is thinner, the blood oxygen data may offer guidance on routine activities, too.

But for most people, the blood oxygen numbers probably don’t say a lot.

As Apple points out, they’re not for medical use—just “wellness” purposes. So, if you’re dealing with a respiratory illness, whether it be asthma or COVID-19, you’re better off using something else.

I found the blood oxygen feature tricky to use, too. To get the readings, the watch shines red and green LEDs and infrared light onto your wrist, then measures the amount of light reflected back to determine the percentage of oxygen your red blood cells are carrying from your lungs to the rest of your body.

To take a real-time reading, you select the Blood O2 app on your watch and then hit “start.” The app will count down 15 seconds, then give you a reading. It automatically runs routine checks, too.

When I started using the feature, I kept getting “unsuccessful measurement” responses. In the troubleshooting guide, Apple advises you to make sure the watch body is flush with your wrist. It also recommends laying your arm flat on your lap or a table, with the display facing up, and keeping your body as still as possible. Cold temperatures, tattoos, and a high heart rate can also affect your results, the company says.

Taking all of that into account helped. I made sure to keep my arm perfectly still. But I also swapped out the watch band I had selected for a slightly smaller one.

The smaller band didn’t give me a reading every time, but it did get the feature to work more consistently. The watch also was able to take a handful of readings in the background at night while I slept.

So I strongly recommend getting a band that fits snugly. One of my CR colleagues used a Series 6 model with an adjustable silicone band, and he had no trouble getting readings.

Charging Dilemmas

Fitbit’s latest smartwatches may offer fewer features than the Apple Watch, but they deliver battery life of three days or longer, which comes in handy when you’re tracking sleep.

By contrast, Apple’s watches have delivered about 18 hours’ worth of battery life. That’s enough to get you through the day, but the device is often running on fumes by bedtime, especially if you track your workouts and add a few cellular calls.

And that makes nighttime applications, like sleep tracking, tough to use.

So when are you supposed to charge your watch? That can be tough to figure out if, like me, you’re used to just plugging it in at bedtime. Apple says the Series 6’s battery will power up in about 90 minutes, so you can quickly top it off right before or after you sleep.

I’ve been charging my watch in the morning; finding the time to do it at night, when I follow less of a routine, is a little harder. More than once, I’ve gotten ready for bed only to discover that the battery level had dropped too low to make it through the night.

The new Apple watches don’t come with the wall adapter needed to plug them into an outlet—they have just a USB cord. This is part of Apple’s new sustainability efforts. As the company points out, lots of people have adapters like those laying around.

But I’m not so sure about that. I get new Apple devices every year for work, but the chargers that come with them rarely make it from one year to the next. And so, they’re generally in short supply for me. And if you have an iPhone 11 Pro, your phone’s wall USB-C charger won’t work with the new watches. 

Shopping for a Band

I normally avoid analyzing Apple’s bands. After all, style is subjective. And Apple offers such a wide variety of choices, there’s generally something for everyone’s taste.

But picking a band is a little more important this time around. A band that rubs you the wrong way could be a nuisance at bedtime. And a poor-fitting band makes the blood oxygen sensor harder to use.

In the past, I’ve been partial to Apple’s Sport Loop bands. They’re made of fabric and close with Velcro, giving you the perfect fit.

For the Series 6, I went with one of Apple’s new Solo Loops. Made of stretchy silicone that fits more like a bracelet, they’re lighter and less bulky than Apple’s traditional silicone sport bands. They come in fun colors—and nine different sizes, too.

To get the right fit, you can print out Apple’s measuring tool, cut it out, and wrap it around your wrist. That sure beats driving to the store. But be careful.

I measured my wrist at home, then had an Apple Store employee double-check the measurement for me, and still ended up with a loop that was too loose. It felt fine but turned out to be one of the reasons I couldn’t get a blood oxygen reading.

So I had to return to the store to get a slightly smaller band. Apple has since updated the online sizing tool. It also has revised its return policy, allowing customers with issues to turn in just the band, not the entire watch, to get a better fit.

The band I have now is very comfortable, and I like the look.

Is the Watch Worth Buying?

Thanks to a handful of little improvements—notably slightly better heart-rate tracking and step-counting accuracy—Apple's Series 6 model is now our top-rated smartwatch.

But when you look at the numbers, it scores just a hair higher than the budget-oriented Apple Watch SE, last year's Apple Watch Series 5, and a few models made by other companies. 

Beyond the blood oxygen sensor, the big hardware improvement in the Series 6 is the faster charging.

So if you don’t feel the need to own the latest and greatest, you might be better off snatching up a Series 5 on clearance. It’s the only other model that contains Apple’s do-it-yourself electrocardiogram feature.

If you’re on a budget, Apple’s Series 3 watch is still, technically, an option at the bargain price of $200, but it’s a few years old.  

For just $80 more, you can get an SE. That watch has much of the same look as the Series 6 and, Apple says, performs at twice the speed of the Series 3. You also get the same accelerometer, gyroscope, and always-on altimeter found on the Series 6.

And the SE works with Apple’s new Family Setup feature and the Fall Detection feature. The Series 3 does not.

But if you have your heart set on a top-of-the-line watch that can handle sleep tracking and give you buckets of wellness-related data, the Series 6 may be what you're looking for.