Between the OnePlus 15 and Xiaomi 15 Ultra, the OnePlus 15 comes out ahead in wired charging and battery capacity, while the Xiaomi 15 Ultra wins on wireless charging and pixel density. Overall, the OnePlus 15 scores 78.4 and the Xiaomi 15 Ultra scores 73.8 on our Mars Score.
Which should you buy?
The OnePlus 15 edges ahead on the Mars Score (78.4 vs 73.8), but the 4.6-point gap is small enough that the right pick comes down to which spec advantages matter to you.
Pick the OnePlus 15 if your top frustration with your current device is running out of charge before the day ends — endurance is the lead spec here. The biggest gaps in its favor are wired charging, battery capacity, weight, among others.
Pick the Xiaomi 15 Ultra if the display is what you stare at all day — refresh rate, brightness, or sharpness is where the difference will be most visible. Its strongest claims are wireless charging, pixel density.
Both ship with comparable ram, main camera, refresh rate, so those specs don't separate the two — focus on the differences below.
Bottom line: there is no wrong answer here — match the spec advantages to how you actually use the product. The Mars Score parity tells you both are well-rounded; the differences are about trade-offs, not quality.
Why OnePlus 15 wins
- ▲Wired charging — 33.33% more. 120 W vs 90 W.
- ▲Battery capacity — 25.00% more. 7500 mAh vs 6000 mAh.
- ▲Weight — 18.00 g less. 211 vs 229.
- ▲AnTuTu — 8.46% more. 2950000 vs 2720000.
- ▲Screen size — 0.74% more. 6.78 " vs 6.73 ".
- ▲Water resistance: IP69 (vs IP68).
- ▲Promised OS updates: 5 (vs 4).
Why Xiaomi 15 Ultra wins
- ▲Wireless charging — 60.00% more. 80 W vs 50 W.
- ▲Pixel density — 16.00% more. 522 ppi vs 450 ppi.
Spec comparison
Design
| Spec | OnePlus 15 | Xiaomi 15 Ultra |
|---|---|---|
| Weight | 211 glead | 229 g |
| Thickness | 8.3 mmlead | 9.4 mm |
| Water resistanceⓘ | IP69lead | IP68 |
| Form factor | bar | bar |
Display
| Spec | OnePlus 15 | Xiaomi 15 Ultra |
|---|---|---|
| Screen sizeⓘ | 6.78 "lead | 6.73 " |
| Pixel densityⓘ | 450 ppi | 522 ppilead |
| Refresh rateⓘ | 120 Hz | 120 Hz |
| Peak brightnessⓘ | 4500 nitslead | 3200 nits |
Performance
Cameras
| Spec | OnePlus 15 | Xiaomi 15 Ultra |
|---|---|---|
| Main cameraⓘ | 50 MP | 50 MP |
| Front camera | 32 MP | 32 MP |
| Optical image stabilizationⓘ | true | true |
Battery
| Spec | OnePlus 15 | Xiaomi 15 Ultra |
|---|---|---|
| Battery capacity | 7500 mAhlead | 6000 mAh |
| Wired chargingⓘ | 120 Wlead | 90 W |
| Wireless chargingⓘ | 50 W | 80 Wlead |
Connectivity
| Spec | OnePlus 15 | Xiaomi 15 Ultra |
|---|---|---|
| 5G supportⓘ | true | true |
| Headphone jack | false | false |
| microSD slot | false | false |
Operating System
| Spec | OnePlus 15 | Xiaomi 15 Ultra |
|---|---|---|
| OS | Android | Android |
| Promised OS updates | 5 yearslead | 4 years |
Frequently asked
Which has better battery, OnePlus 15 or Xiaomi 15 Ultra?+
OnePlus 15 has 25.0% more battery — 7500 mAh vs 6000 mAh.
Which is lighter, OnePlus 15 or Xiaomi 15 Ultra?+
OnePlus 15 is 18g lighter — 211g vs 229g.
Is OnePlus 15 waterproof?+
OnePlus 15 has an IP69 rating.
Does Xiaomi 15 Ultra support 5G?+
Yes, Xiaomi 15 Ultra supports 5G.
Which has a better camera, OnePlus 15 or Xiaomi 15 Ultra?+
Xiaomi 15 Ultra has a 50 MP main camera vs 50 MP.
Spec-level deep dives
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