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Samsung Galaxy S21 Plus vs. Galaxy S21 Ultra: What should you buy?

Samsung Galaxy S21 Plus vs. Galaxy S21 Ultra
(Image credit: Tom's Guide)

If you're after one of the best big phones, Samsung  has an embarrassment of riches. All of the new Samsung Galaxy S21 models have screens that are at least 6.2 inches in size, with the Galaxy S21 Plus and Galaxy S21 Ultra towering above all other options.

The Galaxy S21 Plus offers a 6.7-inch display with an adaptive refresh rate, which is sure to appeal to people who want lots of screen real estate. But the Galaxy S21 Ultra goes even larger, a 6.8-inch panel that also adjusts its refresh rate depending on your screen activity.

Is bigger actually better? To find out the winner of a Samsung Galaxy S21 Plus vs. Galaxy S21 Ultra face-off, we compare the capabilities of both phones to see which offers the most appealing set of features.

Samsung Galaxy S21 Plus vs. Galaxy S21 Ultra: Specs

Galaxy S21 Plus Galaxy S21 Ultra
Starting price$999 $1,199
Display (Resolution; Max. refresh rate)6.7 inches (2400 x 1080) 6.8 inches (3200 x 1400)
Display refresh rate48 Hz to 120 Hz10 Hz to 120 Hz
ChipsetSnapdragon 888Snapdragon 888
RAM8GB12GB, 16GB
Storage128GB, 256GB128GB, 256GB, 512GB
Rear cameras12MP main (f/1.8), 12MP ultrawide (f/2.2), 64MP telephoto (f/2.0) with 3x zoom 108MP main (f/1.8), 12MP ultrawide (f/2.2), 10MP 3x telephoto (f/2.4), 10MP 10x telephoto (f/4.9)
Front camera10MP (f/2.2)40MP (f/2.2)
Battery size4,800 mAh5,000 mAh
Battery life (Hrs:Mins)9:41 (adaptive), 9:53 (60Hz)10:07 (adaptive), 11 hours 25 min (60Hz)
Water ResistanceIP68IP68
Size6.4 x 2.9 x 0.3 inches (161.5 x 75.6 x 7.8mm)6.5 x 2.9 x 0.4 inches (165.1 x 75.6 x 8.9mm)
Weight7.05 ounces (202g)8.08 ounces (228g)

Samsung Galaxy S21 Plus vs. Galaxy S21 Ultra: Price and availability

Samsung cut prices all around on the Galaxy S21 lineup, selling each model for $200 than their Galaxy S20 counterparts. That brings the Galaxy S21 Plus to $999, compared to $1,199 for the S21 Ultra.

The $1,000 threshold is a big psychological barrier when it comes to smartphone shopping So the fact that you can get a Galaxy S21 Plus for less than $1,000 is a big mark in that phone's favor. The S21 Ultra offers more storage options, however. In addition to the 128GB base model, you can get a 256GB version for an extra $50 or a 512GB version for $180 more than the base model. The 256GB Galaxy S21 Plus costs $1,049.

Samsung Galaxy S21 Plus vs. Galaxy S21 Ultra: Design

Unlike the Galaxy S21 and its plastic back, the Galaxy S21 Plus and Galaxy S21 Ultra share a glass back featuring Corning's Gorilla Glass Victus. The result is a more premium feel for both larger phones, though S21 owners may have the last laugh if early Galaxy S21 drop tests are anything to go by.

Samsung Galaxy S21 Plus vs. Galaxy S21 Ultra

From left to right, the Galaxy S21, Galaxy S21 Plus and Galaxy S21 Ultra. (Image credit: Tom's Guide)

Color options vary depending on where you get your phone. Carriers only offer the Galaxy S21 Ultra in Phantom Black and Phantom Silver, but at Samsung.com, you can find the phone in navy blue, titanium or brown. The S21 Plus features black, silver and violet options, with Phantom Red and Phantom Gold available exclusive at Samsung.

Both the S21 Plus and S21 Ultra use Samsung's new contour-cut design where the rear camera array blends into the band around the outside of the phone. The Ultra mixes things up by offering a curved display, which you'll either hail as an elegant design difference or curse that  invites unintended display touches. Like the Galaxy S21, the S21 Plus features a screen with flat edges.

As you might imagine, the Galaxy S21 Ultra is slightly taller than the S21 Plus to accommodate its larger 6.8-inch display, though the S21 Plus is a hundredth of an inch wider. You'll get a heavier phone with the Galaxy S21 Ultra — 8.08 ounces versus 7.05 ounces with the S21 Plus.

Samsung Galaxy S21 Plus vs. Galaxy S21 Ultra: Display

The calling card for the Galaxy S21 lineup has been the adaptive refresh rates on the phones' displays. When you're doing something that benefits from a fast refresh rate, the S21 models will ramp up to 120Hz so you can enjoy smoother scrolling and more immersive gaming (at least in games that support the feature). Do something where the screen is more static, and the display will ratchet down the refresh rate to conserve battery.

Samsung Galaxy S21 Plus vs. Galaxy S21 Ultra

Galaxy S21 Plus and Galaxy S21 Ultra (Image credit: Tom's Guide)

Just how much the screen's refresh rate can slow down is a big differentiating factor between the Galaxy S21 Plus and Galaxy S21 Ultra — certainly bigger than the 0.1-inch difference in screen size. The display on the S21 Ultra can slow down to 10Hz, while the S21 Plus can only slow to 48Hz.

The S21 Ultra's resolution is sharper, too, at 3200 x 1400. The S21 Plus offers a 2400 x 1080 resolution.

While the Galaxy S21 Ultra offers the brighter display of the two phones — we measured it at 821 nits compared to 750 nits for the S21 Plus — you won't need to squint to see either screen in bright sunlight. You'll see slightly more of the DCI-P3 color gamut on the S21 Ultra screen, as it produced 81.4% to the S21 Plus' 73.5%.

Samsung Galaxy S21 Plus vs. Galaxy S21 Ultra: Cameras

The Galaxy S21 Ultra would seem to be the choice for serious mobile photographers. While each phone offers a wide angle lens aided by an ultrawide angle shooter and a telephoto camera, the S21 Ultra simply delivers a bigger main sensor and adds a second telephoto lens. It also supports a larger 100x digital zoom.

Samsung Galaxy S21 Plus vs. Galaxy S21 Ultra

Galaxy S21 Ultra (Image credit: Future)

To be specific, you'll get a 108MP main camera with the Galaxy S21 Ultra along with a laser autofocus sensor to help the camera focus quickly. In addition to the 12MP ultrawide angle camera, you'll have a pair of 10MP telephoto lenses, one that supports a 3x optical zoom and the other that can zoom in at 10x. 

The lone telephoto lens on the Galaxy S21 Plus is a 64MP sensor that supports a 3x zoom; digital zoom is capped at 30x. But like the S21 Ultra, a Zoom Lock feature helps steady the shot by focusing on the subject. Other cameras on the Galaxy S21 Plus include a 12MP main shooter and 12MP ultrawide angle lens.

Samsung Galaxy S21 Plus vs. Galaxy S21 Ultra

Galaxy S21 Plus (Image credit: Tom's Guide)

The Galaxy S21 Ultra proved to be one of the best camera phones in our testing, keeping pace with the iPhone 12 Pro Max. The shots produced by the Galaxy S21 Plus aren't quite up to that standard, but this is still a very good camera phone.

Samsung Galaxy S21 Plus vs. Galaxy S21 Ultra: Performance

On paper, the Galaxy S21 Plus and Galaxy S21 Ultra should deliver similar performance. Both run on Qualcomm's Snapdragon 888 system-on-chip, the best silicon available for Android phones right now. In our Galaxy S21 benchmark testing, that largely proved to be true, though the S21 Ultra has a little extra oomph, thanks to the 12GB of RAM that comes in the base model. (If you opt for the 512GB version of the phone, you get 16GB of memory.) The Galaxy S21 makes do with 8GB of RAM.

Samsung Galaxy S21 Plus vs. Galaxy S21 Ultra

Galaxy S21 Ultra (Image credit: Future)

Running Geekbench 5, the Galaxy S21 Ultra had the better scores, posting an 1,123 result in the single-core test and a 3,440 multicore result. That compares to respective scores of 1,116 and 3,300. In our real-world test — we have the phones transcode a 4K video to 1080p in Adobe Premiere Rush — the S21 Plus actually posted the best time at 1 minute to the S21 Ultra's 1 minute and 2 second result. Essentially, both phones perform the same, though the extra memory should help the S21 Ultra better handle things like multitasking and app switching.

Another thing that's identical on the two phones is 5G connectivity. Both the Galaxy S21 Plus and S21 Ultra support the same 5G bands and work on all 5G networks in the U.S., including Verizon's high-speed Ultra Wideband offering. The S21 Ultra is the only new Samsung phone to support Wi-Fi 6E, an updated wireless standard that promises faster speeds and more bandwidth, provided you've got a compatible router.

Samsung Galaxy S21 Plus vs. Galaxy S21 Ultra: Battery life and charging

The Galaxy S21 Ultra features the bigger battery of these two Samsung phones — 5,000 mAh to 4,800 mAh for the Galaxy S21 Plus. So it's not surprising that the S21 Ultra lasts longer on a charge. What may be surprising, though, is how much longer the S21 Ultra lasts when compared to the Galaxy S21 Plus.

Galaxy S21 Plus (Image credit: Tom's Guide)

On our battery test, where we set phones to surf the web continuously over a cellular connection until they run out of power, the Galaxy S21 Ultra turned in a time of 11 hours and 25 minutes, landing that device on our best phone battery life list. Of course, we got that result by turning off the adaptive display feature; with the faster refresh rate enabled, the S21 Ultra's battery life fell to 10 hours, 7 minutes, which is slightly ahead of the average result for smartphones.

Both results were better than the S21 Plus' performance on our battery test. With the adaptive display turned on, the S21 Plus lasted for 9 hours and 41 minutes. Setting the display to a 60Hz refresh rate, the result improved by only 12 minutes.

Samsung stopped including chargers with every Galaxy S21 model, so you're on your own for a charger with either the S21 Plus or S21 Ultra. We dug up a 25-watt charger to power up the drained phones, and the S21 Ultra got to a 56% charge after half-an-hour.

Samsung Galaxy S21 Plus vs. Galaxy S21 Ultra: Software and special features

Both the Galaxy S21 Plus and Galaxy S21 Ultra ship with Android 11 out of the gate, and the promise of three years' worth of software updates. Samsung also includes the latest version of its One UI interface. One UI 3 features lock screen widgets, new customization options, and an object eraser photo feature for removing unwanted people from photos.

Samsung Galaxy S21 Plus vs Galaxy S21 Ultra

Galaxy S21 Ultra, with S Pen (Image credit: Future)

The Galaxy S21 Ultra gets an extra boost with support for Samsung's S Pen. This is the first time that a phone outside the Galaxy Note lineup can use the S Pen, and while you need to buy the $40 stylus separately, it does give you the ability to draw, sketch and take notes on your phone. You won't find S Pen support on the Galaxy S21 Plus.

Samsung Galaxy S21 Plus vs. Galaxy S21 Ultra: Outlook

The Galaxy S21 Ultra packs in the best features Samsung has to offer for a premium price — though not as premium as Samsung was charging for last year's Ultra model. The Galaxy S21 Plus takes many of those top capabilities, especially the stellar display and its adaptive refresh rate, and offers them in a phone that can be had for less than $1,000.

For that reason, any Samsung Galaxy S21 Plus vs. Galaxy S21 Ultra showdown comes down to whether you value price or features. The S21 Plus is the more affordable of the two new Samsung phones and you get plenty of features in exchange for your dollars. But the wider range of refresh rates, the multiple zoom lenses and the ability to support an S Pen make the Galaxy S21 Ultra the choice for anyone who demands the ultimate Samsung phone.

Philip Michaels
Philip Michaels is a senior editor at Tom's Guide. He has strong opinions about Apple, the Oakland Athletics and old movies. Follow him at @PhilipMichaels.