Samsung Galaxy Z Flip 3 vs. Galaxy S21 Plus: Which $999 Samsung phone should you buy?

This Samsung Galaxy Z Flip 3 vs. Galaxy S21 Plus face-off asks the question: Which $999 Galaxy is better? The answer isn’t cut and dry, and it depends on what’s more important to you. On the one hand, with the Galaxy Z Flip 3, you get a folding phone that’s really pocketable and fun to use. On the other, the Galaxy S21 Plus is a solid device that does just about everything well and looks great while doing so.

The Galaxy S21 Plus has the added benefit of sporting a 3x telephoto lens, plus Samsung’s other zoom magic. People serious about photography may want to look at the S21 Plus over the Galaxy Z Flip 3. In addition, the S21 Plus benefits from a considerably larger battery. 

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However, the Z Flip 3 is more pocket friendly when folded, and its Flex mode gives you more versatility in terms of how you can use this phone. The exterior display is bigger this time around, too, which is a nice upgrde. 

We put both phones head-to-head to see which one came out on top. It’s a close race. Here’s how the Samsung Galaxy Z Flip 3 vs. Galaxy S21 comparison shapes up.

Samsung Galaxy Z Flip 3 vs. Galaxy S21 Plus: Specs

Samsung Galaxy Z Flip 3 vs. Galaxy S21 Plus: Price

For starters, both the Galaxy Z Flip 3 and Galaxy S21 Plus cost the same $999. Both phones come with 128GB of storage and 8GB of RAM, and you can double the storage for another $50. The $1,000 mark is not an easy thing for everyone to handle, which is why the smaller Galaxy S21 for $799 is so appealing.

The Galaxy Z Flip 3, however, is the first foldable to break the $1,000 price barrier, if only just barely. That’s still a serious accomplishment and shows just how fast technology can progress. For this reason, the Flip 3 wins out in this category

Winner: Galaxy Z Flip 3

Samsung Galaxy Z Flip 3 vs. Galaxy S21 Plus: Design

Despite their similarities in other categories, the biggest Samsung Galaxy Z Flip 3 vs. Galaxy S21 Plus difference is the design. The latter is a traditional glass-and-metal slab, albeit a very pretty one. The camera module on the S21 Plus’  back blends seamlessly with the phone’s frame, making it stand out less than other camera arrays that just jut out.

The Galaxy S21 Plus also has a big 6.7-inch Super AMOLED display that’s just beautiful. But the phone is 3 inches wide, which, combined with its 6.4-inch height, makes for a relatively bulky handset. Even if you have big hands, the S21 Plus can be a bit unwieldy. Still, at 7 ounces, it’s not all that heavy considering its size and large battery.

The whole point of the Galaxy Z Flip 3 is that it folds in half vertically. The two displays split along a horizontal axis, and when closed, the Flip 3 is incredibly pocketable. In fact, when it’s closed up, Z Flip 3 is only 3.4 inches tall. That’s crazy small and can fit in many pants pockets. 

When you unfold it, the Flip 3 is 6.5 inches tall and 2.8 inches wide. Despite being just 0.2 inches thinner than the S21 Plus, it feels much more manageable to hold and use in one hand. It’s a minuscule difference on paper, but I loved how narrow the phone felt.

As far as appearances go, the Galaxy S21 Plus looks similar enough to the Galaxy S21 Plus, coming in several pretty colors. I have the Phantom Violet (which is more of a lavender) and it’s quite stunning.

The Galaxy Z Flip 3 is available in three colors, with another three exclusive to Samsung’s website. We got to spend some time with the lavender and cream options and both look really nice. And the Flip 3 doesn’t look much like the original Galaxy Z Flip. Not only is the camera module different, but the new, larger cover display gives our review unit a two-tone look. It reminded me of the old Pixel design language that Google used for the first three generations of its phones. 

The winner in this category comes down to personal preference, but we have to give the nod to the Galaxy Z Flip 3 simply for its novelty and unique design. Foldables are still new and fun, and definitely break the monotony of typical smartphone design.

Winner: Galaxy Z Flip 3

Samsung Galaxy Z Flip 3 vs. Galaxy S21 Plus: Display

Both the Galaxy Z Flip 3 and Galaxy S21 Plus feature 6.7-inch Super AMOLED displays with 120Hz refresh rates. They’re both spectacular screens and it’s hard to pick one as better than the other.

In our lab testing, the Galaxy S21 Plus managed 212.3% of sRGB and 150.4% of DCI-P3. For its Delta-E color accuracy rating, the S21 Plus got a 0.18 (where 0 is perfect). The Galaxy Z Flip 3, meanwhile, reproduced 102% of the sRGB spectrum and 76.4% of the DCI-P3 color space. The Flip 3's Delta-E score was a much higher 0.32. 

Of course, I can't go without mentioning the crease that bisects the two displays across the horizontal axis. You can definitely feel it when you drag your finger over it, and it’s rather visible in daylight or in apps that use light mode — it appears as a slight distortion in the image on screen. This might be off-putting for some people and takes getting used to.

The Galaxy S21 Plus' display is better in testing, and that's why it wins this section. Just know that, in practice, both phones have great displays that look quite similar in most conditions (the crease on the Galaxy Z Flip 3 aside).

Winner: Galaxy S21 Plus

Samsung Galaxy Z Flip 3 vs. Galaxy S21 Plus: Cameras

The Galaxy Z Flip and Galaxy S21 Plus have mostly similar cameras, though the S21Plus features something the Flip doesn’t  — a dedicated telephoto lens with a 3x optical zoom and 30x digital zoom. The Flip 3 relies entirely on digital zoom with a max of 10x.

The Galaxy Z Fold 3 has a 12MP (f/1.8) wide-angle main camera and a 12MP (f/2.2) ultrawide camera. The Galaxy S21 Plus has the same hardware, other than that64MP (f/2.0) telephoto lens. Around the front, the Flip 3 has a 10MP (f/2.4) selfie cam, while the S21 Plus also a 10MP front-facing camera, but with a f/2.2 aperture.

To kick off this camera comparison, we have these flowers. Both photos look extremely similar. They both have the characteristic Samsung saturation, which remains polarizing — some people love it, others don’t. That said, both the Flip 3 and S21 Plus put out great photos and this is no exception.  

This second outdoor shot of different flowers tells the same story. The lighting is pretty decent, though both phones struggle a bit with overexposure. The white flowers look a bit too bright in the bottom right of the image. But again, these pictures are functionally identical and pretty good.

Moving inside, the two photos turn out quite different shots. Immediately, you can see that the Flip 3’s image is darker than what the S21 Plus produced. While the Flip 3’s effort is dimmer, the colors in the S21 Plus’ look a bit overexposed. Brightness does not equal vibrancy. Neither shot is bad, but I give the point to the Flip 3.

With portraits, the S21 Plus acts more like a phone from Apple or Google by zooming in in on my face. The Flip 3 zoomed out, which takes the focus off the subject (me). However, the Flip 3’s portrait is warmer and richer, making the lines and colors of my face pop more. The S21 Plus’ image is a bit too soft for my liking. The Flip 3, despite looking less artistic, has a more color-accurate photo.

Another huge difference between the two phones comes down to the night mode. Right off the bat, the Galaxy S21 Plus wins. Its image is brighter with sharper details than the Flip 3’s. While you can still make out the smoker in the Flip 3’s shot, the S21 Plus is just so much better.

Here’s a zoom comparison. Again, this one speaks for itself — 10x is just hard to compare to 30x.

In this selfie comparison, the subtle differences can be slightly difficult to spot. The biggest one is the temperature. The Flip 3’s selfie, shot with its 10MP front camera, is cooler than the S21 Plus’. This softens the natural red tones in my face and doesn’t look quite right to me. I prefer the S21 Plus selfie. Both photos have good focus, but I prefer the color reproduction in the S21 Plus image.

I should mention that you can take a selfie with the Galaxy Z Flip 3’s rear cameras when the phone is folded up. In this instance, you often will get a richer image than the 10MP front-facing cam can put out, but lining up the shot just so on the cover display takes some practice. The end results, however, look great and I recommend this route for selfies if you pick up a Flip 3.

Winner: Galaxy S21 Plus

Samsung Galaxy Z Flip 3 vs. Galaxy S21 Plus: Performance

Both the Galaxy Z Flip 3 and Galaxy S21 Plus use a Snapdragon 888 and 8GB of RAM. This is a powerful combination. As such, you’d expect them to perform very similarly.

We don’t have the benchmarks for the Galaxy Z Flip 3 yet, but from the time we’ve had with the phone, it performs very well. It’s hard to make a Snapdragon 888 device stumble and the Flip 3 is no exception, as the foldable phone played the most intensive games without any problems.

The Galaxy S21 Plus does set a high bar with benchmarks. In Geekbench 5, it hit a flat 3,300 in multicore. This is a good score and pretty average for the Snapdragon 888. In the intense 3DMark Wild Life Unlimited graphics test, the S21 Plus managed an average fps of 33.37. 

The Galaxy Z Flip 3 performed slightly worse with a 2,984 in Geekbench 5 multicore and an average fps of 27.3 in Wild Life Unlimited. Like with the display section, these might look like a serious gap between the two phones, but they both handle similarly in real life. That said, we have to give the nod to the Galaxy S21 Plus.

Winner: Galaxy S21 Plus

Samsung Galaxy Z Flip 3 vs. Galaxy S21 Plus: Battery and charging

Other than the physical differences, a spot where the Galaxy Z Flip 3 and Galaxy S21 Plus diverge is battery capacity. The S21 Plus has a large 4,800 mAh battery, while the Flip 3 makes do with a much smaller 3,300 mAh battery. In fact, that’s the same capacity as the original Galaxy Z Flip.

The Tom's Guide battery life test tasks phones to endlessly reload web pages on a cellular connection at 150 nits of brightness. The Galaxy S21 Plus, which lasted 9 hours and 41 minutes in adaptive mode; with the display locked at 60Hz, the phone lasted for 9 hours and 53 minutes. Neither is a great result, but it's far better than the Galaxy Z Flip 3.

In the foldable's adaptive refresh rate mode, it managed just 5 hours and 43 minutes. At 60Hz, that went up slightly to a flat 6 hours. It's pretty obvious that the Galaxy S21 Plus wins this one.

Winner: Galaxy S21 Plus

Samsung Galaxy Z Flip 3 vs. Galaxy S21 Plus: Software and special features

Samsung has done a good job of creating a unified software experience across its mobile device portfolio. One UI is pretty solid these days and it’s definitely what a lot of people think of when they think of Android. 

Both the Galaxy Z Flip 3 and Galaxy S21 Plus come with Android 11 out of the box, which as that’s the latest version of Google’s phone software. Android 12 is right around the corner, though, so we’ll hopefully see it land on Samsung’s phones later this year.

On the surface, both phones are identical in terms of software. However, Samsung put a few extra features on the Galaxy Z Flip 3 to take advantage of the dual screens. It’s called Flex mode and it’s much better this time around than it was on the original Galaxy Z Flip. Basically, certain apps will split themselves between the two screens when you have the phone flexed (not fully open).

On the surface, both phones are identical in terms of software. However, Samsung put a few extra features on the Galaxy Z Flip 3 to take advantage of the dual screens. It’s called Flex mode and it’s much better this time around than it was on the original Galaxy Z Flip. Basically, certain apps will split themselves between the two screens when you have the phone flexed (not fully open).

The two best examples of this are the Camera and YouTube apps. In the former, you can angle the top half of the phone however you want. That’s where you’ll find the viewfinder, with the shutter controls on the lower portion of the phone. It’s pretty neat. And in YouTube, you can watch the video in the top section while scrolling through comments or suggested videos on the lower half.

As you might expect, the extra features on the Galaxy Z Flip 3 give it the advantage here. The Galaxy S21 Plus still has plenty of things going on, but the Flip 3 just has a smidge more. 

Winner: Galaxy Z Flip 3

Samsung Galaxy Z Flip 3 vs. Galaxy S21 Plus: Overall winner

The Galaxy S21 is the winner of this face-off. It wins primarily because of its superior battery life, and it just barely eked out a victory in the camera and display categories. It also has the added benefit of having a dedicated telephoto lens, instead of relying on digital zoom like the Galaxy Z Flip 3 does.

Neither is cheap — $1,000 is still a lot to pay for a phone — and it’s hard to say how well the Galaxy Z Flip 3 will hold up long-term. The best reason to get the Z Flip 3 is the fun and compact foldable design; if you want a phone that truly stands out, this is it. But the S21 Plus is the phone to get for those who want a bigger battery and a telephoto zoom.