Xiaomi 15 Ultra vs. Samsung Galaxy S25 Ultra

There’s more than one way to skin a cat make an Ultra-grade smartphone and the Samsung way isn’t the Xiaomi way. The Galaxy S25 Ultra is aiming to be the most feature-rich Android while, in the process, having a camera that’s very good. The Xiaomi 15 Ultra, on the other hand, is more of a camera-with-a-phone-attached type of deal. We’ll try to compare the two on all the metrics and then look at some pictures to help you decide which one is best for you.

Table of Contents:

For starters, you can compare the complete specs sheets or directly continue with our editor’s assessment in the following text.

Size comparison

All the top-of-the-line models are full-size handsets with no real aspirations for compactness. But there are nuances between these two. The Galaxy S25 Ultra is notably boxier than the Xiaomi – flat display and back, flat sides, sharp corners – it makes quite a bulky impression. Sure, it’s somewhat significantly thinner and marginally lighter, but it’s the 2.3mm of extra width that are a lot more easily felt. Meanwhile, the Xiaomi’s more fluid shapes tend to be a lot easier on both your hands and your pocket. That said, the 15 Ultra’s huge camera assembly can get in the way all by itself – the almost hidden cameras of the Galaxy barely register.

In the hand: Xiaomi 15 Ultra • Galaxy S25 Ultra

The Galaxy’s display is protected by an exclusive type of Corning-made glass-ceramic, the Gorilla Armor 2. The handset’s back is an older variety – Gorilla Glass Victus 2. The S25 Ultra is the second-gen Galaxy with titanium used for its frame and it’s a higher grade too this year.

In contrast, the Xiaomi 15 Ultra uses its house-branded Shield Glass 2.0 for its display. The backs are either eco leather or glass fiber and the frame is aluminum. We’re not exactly sure how much better the Galaxy’s materials are from a longevity standpoint, but it sure does sound like it’s built tougher. Both phones are IP68-rated for dust and water resistance (down to 1.5m for 30 minutes).

Color options are more varied on the Galaxy, with up to 7 colorways in existence, though three of them are limited to the company’s official online store (where available) and none is particularly interesting. The Xiaomi’s glass fiber-backed options are Black and White, and there’s also the two-tone rangefinder camera-like eco leather option. We’d say the Xiaomi has more personality.

The Galaxy S25 Ultra has the S Pen to set it apart from any other phone, the built-in stylus being a boon to productivity, though it has lost a key feature this year – the camera remote functionality. The Xiaomi 15 Ultra has a unique accessory of its own, albeit one that comes at an extra cost – the Photography kit that makes it look and behave even more like a camera and less like a phone.

Accessories: Xiaomi Photography kit (optional) • Galaxy S Pen (always there)

Display comparison

Xiaomi has been putting out 12-bit displays with 68B color support for a while now, even on relatively inexpensive models, so it’s no wonder that the 15 Ultra has such a panel. The Galaxy, meanwhile, is stuck in the past with an 8-bit 16M color panel. How important that would be to you is debatable but it’s one of the main differences when it comes to display. The other differentiator is HDR standards support – the Xiaomi has them all covered, including Dolby Vision, while the Galaxy is sticking to HDR10+.

Of course, both screens are OLED, with plenty of pixels, and adaptive refresh rate in the 1-120Hz range. The one on the Galaxy is slightly larger, while the Xiaomi display is a little bit brighter, but the S25 Ultra is less reflective to make up for it.

Of course, the S Pen is a major selling point for the Galaxy – mentioned here, because it’s mostly the layers in the display stack that are doing the work.

Battery life

The Xiaomi Ultra got a battery upgrade this year and it has 5,410mAh vs. 5,000mAh on the Galaxy S25 Ultra.

The battery test numbers we got out of the Xiaomi are generally better than the Galaxy’s, though the differences aren’t huge. Most significant is the 15 Ultra’s lead in web browsing, while the voice call and gaming test advantage is smaller. Video playback turned out essentially the same between the two in our testing. Overall, a win for the Xiaomi.

Charging speed

You’d think the 15 Ultra would take an easy and decisive win for charging speed, looking at the 90W vs. 45W power ratings. In practice, things are essentially tied at the 15-minute and 30-minute checkpoints, with the Xiaomi snatching a small victory in the race to 100%. That said, you could argue that being a little quicker with a little larger battery adds up to a moderately-sized victory.

Both phones feature wireless charging, with some specifics potentially making one better than the other for certain users. The Xiaomi can go as high as 80W, nearly matching the wired option in terms of speed (though you obviously need to buy the proprietary peripherals to get there). The Galaxy maxes out at 15W, but it’s Qi2.1 compliant, so maybe it will get your brand new car’s charging coils to auto align (a bit of a niche feature, we reckon).

Speaker test

You get the usual stereo speaker arrangement on both phones – one speaker on the bottom, and another one up top that also covers earpiece duty. Both handsets earned ‘Very Good’ ratings for loudness in our testing, with a minor advantage for the Xiaomi in the integrated loudness result. There are small differences in the tuning, but ultimately both phones just sound great – we don’t think there’s enough separating them that you’ll be picking one over the other based on speaker quality.

Performance

The Xiaomi 15 Ultra is powered by the Snapdragon 8 Elite chipset, Qualcomm’s flagship silicon for 2025. The S25 Ultra has sort of the same SoC inside, though Samsung and Qualcomm might want you to believe that the Galaxies are special by slapping a ‘for Galaxy’ at the tail end of the chip’s name.

The global 15 Ultras are typically available in a 16GB/512GB flavor, while you can get the global Galaxy S25 Ultra anywhere from 256GB up to 1TB (all with 12GB RAM).

Benchmark performance

In benchmarks, the Galaxy has a minor advantage under multi-core CPU load (essentially identical results under single-core) and a minor edge in some GPU applications. Weirdly enough, the Galaxy is trailing in Antutu across all the disciplines in the test. Ultimately, both phones are plenty powerful and deliver a smooth user experience.

When it comes to software support, the Galaxy comes with a promise for 7 years of major OS upgrades and ongoing security patches. Xiaomi says you can expect 4 OS upgrades and 6 years of security support. We wouldn’t say the Galaxy’s extra years offer a significant advantage over the Xiaomi, though more is more and there might be that one person that will appreciate it.

There’s also the general notion that we have that One UI is the most feature-rich take on Android, with wide-ranging capabilities beyond the basics. That includes the tight collaboration with Google on the AI stuff which tends to put Galaxies a notch above the rest. The HyperOS on the Xiaomi is nice in its own right, just not quite on the same level.

Camera comparison

High-end Galaxies know a thing or two about taking pictures and the S25 Ultra has a quad-camera setup on its back with wide-ranging capabilities. There are two telephotos – one at 3x zoom, the other at 5x, a new ultrawide this time around, and a 200MP main camera. The thing is, none of the modules are all that exciting or cutting-edge – they’re just solid bits that don’t spark much enthusiasm.

The Xiaomi is very different. For one, it’s got a 1-inch type sensor on its main camera – seemingly the only remaining globally available smartphone with an imager of this size. Sure, this camera has lost the variable aperture lens of the previous generation, but that’s perhaps an easy pill to swallow.

The other exciting bit is the longer of the two telephotos, which pairs a 100mm-equivalent lens (4.3x) with a 200MP 1/1.4″ sensor – one of our favorite pieces of camera hardware of the past year. The shorter telephoto, a 70mm (3x) 50MP unit can focus super close, adding another level of versatility to the setup.

Image quality

Photos from the main cameras look great from both phones, though there might be small advantages here or there. We’d say the 15 Ultra delivers better sharpness across the whole frame and generally crispier detail. Perhaps a little subjective, but we’re also liking the Xiaomi’s shadow development better too, though the Galaxy’s contrastier take is, in a way, more accurate. So too are the Samsung’s slightly more neutral colors, though it’s not like the Xiaomi is really too far off.

The 15 Ultra tends to be the better option for people shots at 1x too – it’s better at gathering photons in dimmer or generally more difficult lighting, plus it has a marked edge in terms of subject separation without going into Portrait mode.

Daylight photo samples, 1x: Xiaomi 15 Ultra • Galaxy S25 Ultra

The Xiaomi offers superior detail definition at 2x – the Galaxy is doing a solid job, but the 15 Ultra is simply better.

Daylight photo samples, 2x: Xiaomi 15 Ultra • Galaxy S25 Ultra

At 3x, the Xiaomi continues to have a meaningful advantage in resolution. It’s also, once again, a better option for portraits.

Daylight photo samples, 3x: Xiaomi 15 Ultra • Galaxy S25 Ultra

It’s the longer telephotos where things get more interesting. The Xiaomi’s 4.3x camera captures nicer shots in most conditions, with extra detail and generally superior rendition when examining on a pixel level. Portraits also benefit from the large sensor/bright lens combination on the Xiaomi.

Daylight photo samples: Xiaomi 15 Ultra (4.3x) • Galaxy S25 Ultra (5x)

At twice the zoom of the longer telephotos, the balance is a little bit weird. We’d have thought the Xiaomi would be scoring easy victories here, but its results can be a little hazy on occasion. When the Xiaomi is sharp, it’s proper sharp, and when it isn’t, it’s still at least as detailed as the Galaxy.

Daylight photo samples: Xiaomi 15 Ultra (8.6x) • Galaxy S25 Ultra (10x)

The ultrawides offer comparable quality, with minor differences here or there. If forced to choose, though, we’d pick the Xiaomi.

Daylight photo samples, 0.6x: Xiaomi 15 Ultra • Galaxy S25 Ultra

Some of the finer nuances between these two phones are in their close-up capabilities. The Galaxy can take 5x photos from as close as 25cm, while the Xiaomi’s 4.3x camera doesn’t like anything closer than 40cm.

The Xiaomi’s 3x camera, on the other hand, can focus as close as 9cm, while the Galaxy’s counterpart needs at least twice that distance for a sharp photo (in addition to not being as sharp in the first place). Ultimately, you’d get the highest reproduction ratio from the 15 Ultra’s 3x camera.

Close-up photo samples: Xiaomi (3x) • Galaxy (3x) • Xiaomi (4.3x) • Galaxy (5x)

Selfies are simply nicer on the Galaxy. Basically, it’s got the right resolution sensor plus autofocus – two areas where Xiaomis have been challenged for years on end.

Selfie samples: Xiaomi 15 Ultra • Galaxy S25 Ultra

In the dark, the 15 Ultra’s main camera is easily our first choice here. It’s sharper, cleaner, and with a wider dynamic range than the Galaxy.

It’s worth mentioning that the Galaxy doesn’t do a whole lot of Night mode processing by default, but you can force its Night mode on, which will result in photos that are similarly not on the same level as the Xiaomi’s, but this time they’ll have different shortcomings than in the regular mode. On the other hand, the Xiaomi just doesn’t have a Night mode, strictly speaking – it’s got a very competent auto Photo mode instead.

Low-light photo samples, 1x: Xiaomi 15 Ultra • Galaxy S25 Ultra

Somewhat unexpectedly given the 1x results in the dark and the 2x results during the day, the Galaxy actually has the upper hand in low-light at 2x.

Low-light photo samples, 2x: Xiaomi 15 Ultra • Galaxy S25 Ultra

We’d call the 3x results in favor of the Xiaomi as well – its shots are typically sharper and cleaner.

Low-light photo samples, 3x: Xiaomi 15 Ultra • Galaxy S25 Ultra

Zooming in a notch further, it’s a closer call between the Xiaomi’s 4.3x telephoto and the Galaxy’s 5x unit. The Xiaomi is notably cleaner next to a rather noisy Galaxy, and we’d say the Xiaomi has a detail advantage, but the Galaxy is keeping up well despite its inferior hardware.

Low-light photo samples: Xiaomi 15 Ultra (4.3x) • Galaxy S25 Ultra (5x)

At 8.6x vs. 10x zoom, it’s something of a toss-up between the often dreamy Xiaomi and the quite noisy Galaxy. Neither is perfect, both are pretty decent each in its own way.

Low-light photo samples: Xiaomi 15 Ultra (8.6x) • Galaxy S25 Ultra (10x)

Comparing the ultrawides, the Galaxy somehow emerges victorious, its images having a small but consistent edge in sharpness.

Low-light photo samples, 0.6x: Xiaomi 15 Ultra • Galaxy S25 Ultra

Video quality

Below we have a few framegrabs from the videos taken by the two phones at each focal length so it’s easier to compare to one another.

Both phones offer wide-ranging video recording capabilities with 4K60 across the board, and 8K and 4K120 on some cameras. The Xiaomi can record in Dolby Vision, unlike the Galaxy. Both phones have Pro video modes too.

The Xiaomi is a tad sharper when comparing ultrawide footage, while the 1x zoom level results are virtually indistinguishable, while at 2x it’s also more or less a tie.

Daylight video samples, 0.6x: Xiaomi 15 Ultra • Galaxy S25 Ultra

Daylight video samples, 1x: Xiaomi 15 Ultra • Galaxy S25 Ultra

Daylight video samples, 2x: Xiaomi 15 Ultra • Galaxy S25 Ultra

At 3x zoom, the Xiaomi has a meaningful advantage, while at 4.3x vs. 5x it’s more of a marginal difference in the 15 Ultra’s favor. Similarly, at 10x on both phones (the Xiaomi doesn’t have a 2x toggle for video on its telephoto to get to 8.6x so we figured 10x vs 10x makes sense) we’re inclined to give the 15 Ultra the nod.

Daylight video samples, 3x: Xiaomi 15 Ultra • Galaxy S25 Ultra

Daylight video samples: Xiaomi 15 Ultra (4.3x) • Galaxy S25 Ultra (5x)

Daylight video samples, 10x: Xiaomi 15 Ultra • Galaxy S25 Ultra

In the dark, the ultrawides are neck and neck, while the Galaxy has a minor edge at 1x (much to our surprise), and a more significant advantage at 2x (a development that’s bordering on astonishing).

Low-light video samples, 0.6x: Xiaomi 15 Ultra • Galaxy S25 Ultra

Low-light video samples, 1x: Xiaomi 15 Ultra • Galaxy S25 Ultra

Low-light video samples, 2x: Xiaomi 15 Ultra • Galaxy S25 Ultra

At the higher zoom levels, it’s hard to call a winner – there’s just not enough of a difference between the two.

Low-light video samples, 3x: Xiaomi 15 Ultra • Galaxy S25 Ultra

Low-light video samples: Xiaomi 15 Ultra (4.3x) • Galaxy S25 Ultra (5x)

Low-light video samples, 10x: Xiaomi 15 Ultra • Galaxy S25 Ultra

Verdict

The Xiaomi 15 Ultra brought some improvements to a camera system that was already among the best ones in the industry, possibly the best you can get outside of China anyway. The new model’s enhanced telephoto capabilities put it in a class of its own, and the 1-inch-type main camera is even more of a standout feature in 2025 than it was in 2024. The Xiaomi is also a great smartphone around the whole camera thing, with a wonderful display and excellent battery life.

The Galaxy S25 Ultra, meanwhile, has the occasional flash of greatness in the camera department, but is happier in maintaining more of a ‘solid cameraphone’ image than a ‘superb cameraphone’ one. That’s pretty much its ethos across the board, actually, making it an overall top choice for pretty much everyone after a high-end phone – particularly those that enjoy having a stylus at all times and those who appreciate Samsung’s tight integration with Google in the software field. Additionally, there is the price consideration as well. The S25 Ultra may have launched at the same price as the Xiaomi 15 Ultra, but it has already gone down in price since its launch, so it is the better deal at the moment.

We’ll end the way we started – the Xiaomi 15 Ultra is for the photographers first and foremost, the Galaxy S25 Ultra is for the… regular people.