We may earn a commission if you make a purchase from the links on this page.
Samsung's foldable phone strategy finally has its most mature representative - the Galaxy Z Fold 3 - which, together with the "rigid" Galaxy S21 Ultra, are the only two Samsung phones with S Pen stylus support you are getting in 2021, thus warranting a direct comparison.
Yep, there will be no Galaxy Note 21 as Samsung deprecated the Note line for the sake of the Ultra and Fold series that are taking over in doodling duties. Makes sense, as on the 6.8" panel listed in the S21 Ultra specs one might use the S Pen as occasionally as on the Note 20, while the giant 7.6" Galaxy Z Fold 3 display is much more conducive for the task.
Here are the main feature and performance differences of Samsung's 2021 S Pen-laden warriors in a thorough Galaxy Z fold 3 vs S21 Ultra comparison.
Samsung Galaxy Z Fold 3 vs Galaxy S21 Ultra displays and S Pen support
Ersatz Galaxy Note replacements
Surprise, surprise, both phones have no silo to slot an S Pen stylus in, so they resort to tack-on cases for these duties. The Note Pack S Pen Fold edition of the Z comes tucking the stylus in the hinge crease which is a rather brilliant move, while the S21 Ultra has a dedicated S Pen case that keeps it on the side, enlarging the already big phone further in width.
Speaking of dimensions, the size of the Z Fold 3 when unfurled is, as expected, much larger even than the gargantuan S21 Ultra. When you close the Fold 3, however, its tall and narrow 6.2" external display makes it actually smaller and easier for one-handed operation with your thumb only. If you discard the abominable thickness and weight, that is, and those really feel uncomfortable in the palm.
If you think that you can never forget carrying a 8.04 oz (229.0 g) phone in your pocket, try it with a 9.56 oz (271.0 g) stack that is more than half an inch thick. Oh, well, life could always be worse, especially when you tack on the Galaxy Z Fold 3's Note Pack S Pen edition case that makes it even thicker and heavier.
On the plus side, the 7.6" 120Hz display of the Z Fold 3 is more of a joy to look at than the 6.8" panel of the S21 Ultra, with less pronounced crease in the middle, new cover material and layers that make it much more durable.
The sheer size of it when unfurled is emphasized even more by the fact that there is no ugly front camera punch hole or notch of any kind, as the selfie snapper is hidden under the display. Now with an S Pen support, the display of the Z Fold 3 really dethrones the S21 Ultra screen from the perch of the best Samsung phone panel so far.
The CIE 1931 xy color gamut chart represents the set (area) of colors that a display can reproduce, with the sRGB colorspace (the highlighted triangle) serving as reference. The chart also provides a visual representation of a display's color accuracy. The small squares across the boundaries of the triangle are the reference points for the various colors, while the small dots are the actual measurements. Ideally, each dot should be positioned on top of its respective square. The 'x: CIE31' and 'y: CIE31' values in the table below the chart indicate the position of each measurement on the chart. 'Y' shows the luminance (in nits) of each measured color, while 'Target Y' is the desired luminance level for that color. Finally, 'ΔE 2000' is the Delta E value of the measured color. Delta E values of below 2 are ideal.
The Color accuracy chart gives an idea of how close a display's measured colors are to their referential values. The first line holds the measured (actual) colors, while the second line holds the reference (target) colors. The closer the actual colors are to the target ones, the better.
The Grayscale accuracy chart shows whether a display has a correct white balance (balance between red, green and blue) across different levels of grey (from dark to bright). The closer the Actual colors are to the Target ones, the better.
Sketch, doodle, and annotate with ease, there will always be a canvas space to do it with inertia instead of scooching your handwriting towards the end of a panel that is just 0.35 inches across. No comparison with the 5 inches of main display width that the Z Fold 3 has to offer here.
Samsung Galaxy Z Fold 3 vs Galaxy S21 Ultra specs and performance
The mighty Snapdragon 888 that is powering both the Z Fold 3 and Galaxy S21 Ultra leaves no stone unturned when it comes to performance with eight cores some of which can peak at 2GHz+ clock speeds when needed.
Granted, the Z Fold 3 doesn't have the whopping 16GB RAM pack of the top S21 Ultra version, but then again its storage starts from 256GB for the base model which is arguably more important than the RAM amount in everyday usage. 12GB RAM on the Z Fold 3 is still plenty, and the phone wouldn't feel underpowered at all, judging from the benchmark comparison between Samsung's top flagships of '21.
AnTuTu is a multi-layered, comprehensive mobile benchmark app that assesses various aspects of a device, including CPU, GPU, RAM, I/O, and UX performance. A higher score means an overall faster device.
If the T-Rex HD component of GFXBench is demanding, then the Manhattan test is downright gruelling. It's a GPU-centric test that simulates an extremely graphically intensive gaming environment that is meant to push the GPU to the max. that simulates a graphically-intensive gaming environment on the screen. The results achieved are measured in frames per second, with more frames being better.
As you can see, the performance scores are rather comparable which is important as the S Pen support would warrant much greater multitasking abilities that the phones can support with aplomb.
Samsung Galaxy Z Fold 3 vs Galaxy S21 Ultra camera
Samsung's first hidden camera is cool, but not enough to nudge you away from the Ultra's top-shelf kit
If there is one area where the "rigid" Galaxy S21 Ultra definitely outshines its flexible Z Fold 3 brethren, it's the record-setting camera kit. The 108MP main camera that is able to capture amazing amounts of detail, the 40MP selfie shooter, and the 10x periscope zoom camera can't be matched by the Z Fold 3's puny triple 12MP set.
The Galaxy Z Fold 2 had a camera kit that's nothing to write home about, and given that the Z Fold 3 inherits it almost literally, there is no contest with the camera prowess of the S21 Ultra. Still, the photos from the Fold 3 are not half bad, as you can see in our camera samples below.
Samsung has a trick up its sleeve when it comes to the selfie camera, though, as the Fold features its first under-panel (UPC) camera unit. Tucked beneath the display layers, it is the reason for the amazing screen-to-body ratio of the phone when unfurled - no ugly notches, punch holes, or pop-ups.
On top of that, Samsung was smart to go with a 4MP unit with gigantic 2 micron pixels to compensate for any light restriction that results from the layers above the sensor. Still, the "uncovered" 40MP unit on the S21 Ultra is likely to produce better selfies, yet the UPC shooter on the Fold is on the main display, so you are more likely to use it for video chats, and fire up the 10MP snapper of the main display for selfies, so it all evens out.
Here are some under-display camera samples from the Z Fold 3 to gauge the quality, again not half bad, even indoors.
Z Fold 3 under-display camera vs S21 Ultra selfie samples
Samsung Galaxy Z Fold 3 vs Galaxy S21 Ultra battery life and charging speeds
The Ultra wins, fatality!
Another area where the Galaxy S21 Ultra outshines the Z Fold 3, after its camera prowess, is the battery department. Not only does it offer a huge 5000mAh battery pack, compared to the two Fold batteries with cumulative 4380mAh capacity, but it also has to power a much smaller, tall 6.8" display, against the nearly square 7.6" panel of the Z Fold 3.
Thankfully, you'll mostly be using the external 6.2" screen of Samsung's foldable phone, so the battery will be enough to power you through the day, but game or browse for a prolonged period, and the Z Fold 3's battery life would quickly dwindle. The S21 Ultra, on the other hand, is the phone with the best battery life in its top-shelf class, able to last you day and a half and even a weekend with moderate usage.
On top of that, it is charged very quickly, for an hour and change, even though it has "just" a 25W charger. The same brick comes with the Z Fold 3, though, so it'd charge slightly faster considering the smaller battery.
Samsung Galaxy Z Fold 3 vs Galaxy S21 Ultra price, or which one to buy
Pricey and worth it
$1799 (256GB) vs $1379 (512GB)
At first brush, the wins that the S21 Ultra notched in the camera and battery sections should warrant an overall comparison trophy given the price difference. After all, while the base Z Fold 3 comes a Benjamin or so cheaper than the Z Fold 2 at launch, it is still far from the top S21 Ultra version with 512GB storage.
Open the giant 7.6" display which can fit two Ultra panels and still have place to doodle with the S Pen on the margins, and all pricing considerations may go out of the window, moreso when Samsung gives you those sweet Z Fold 3 preorder and trade-in bonuses to offset the price difference: