Redmi K40S vs Xiaomi 15 Ultra
The Redmi K40S (2022) runs on the Qualcomm Snapdragon 870 5G, while the Xiaomi 15 Ultra (2025) runs on the Qualcomm Snapdragon 8 Elite. By overall MobileRank rating, the Xiaomi 15 Ultra leads — 85/100 vs 54/100 (a 31-point difference). Key differences: the Xiaomi 15 Ultra has the bigger battery (6000 mAh vs 4500); the main camera is 48 MP vs 50 MP; the Xiaomi 15 Ultra is faster in AnTuTu (3,030,376 vs 1,010,069); the Redmi K40S is noticeably lighter (195g vs 225g).
Profile comparison
Category scores
Redmi K40S
Xiaomi 15 Ultra
What makes Redmi K40S better?
- Lighter: 195g vs 225g
- Better portability (65/100 vs 29/100)
What makes Xiaomi 15 Ultra better?
- Higher AnTuTu: 3030376 vs 1010069
- Better Geekbench Single: 3050 vs 1298
- Better Geekbench Multi: 10200 vs 3520
- Bigger battery: 6000 vs 4500 mAh
- Faster charging: 90W vs 67W
- Better main camera: 50MP vs 48MP
- Higher performance (92/100 vs 61/100)
- Better camera (87/100 vs 36/100)
- Longer battery life (80/100 vs 42/100)
- Better display (90/100 vs 79/100)
Comparison verdict
Comparing the Redmi K40S vs the Xiaomi 15 Ultra, the Xiaomi 15 Ultra scores 31 points higher (85/100 vs 54/100). In the "performance" category, the Xiaomi 15 Ultra leads (92/100 vs 61/100). In the "camera" category, the Xiaomi 15 Ultra leads (87/100 vs 36/100). In the "battery" category, the Xiaomi 15 Ultra leads (80/100 vs 42/100). In the "performance" category, the Xiaomi 15 Ultra significantly outperforms the Redmi K40S (92/100 vs 61/100). In the "display" category, the Xiaomi 15 Ultra is a bit better (90/100 vs 79/100). In the "camera" category, the Xiaomi 15 Ultra significantly outperforms the Redmi K40S (87/100 vs 36/100). In the "battery" category, the Xiaomi 15 Ultra significantly outperforms the Redmi K40S (80/100 vs 42/100). In the "portability" category, the Redmi K40S significantly outperforms the Xiaomi 15 Ultra (65/100 vs 29/100).
Specs comparison
| Specification | Redmi K40S | Xiaomi 15 Ultra | |
|---|---|---|---|
| Processor | Qualcomm Snapdragon 870 5G | Qualcomm Snapdragon 8 Elite | |
| AnTuTu | 1010069 | 3030376 | |
| Geekbench Single | 1298 | 3050 | |
| Geekbench Multi | 3520 | 10200 | |
| Display | 6.7" AMOLED | 6.7" LTPO AMOLED | |
| Resolution | 1080x2400 | 3200x1440 | |
| Refresh rate | 120 Hz | 120 Hz | |
| Battery | 4500 mAh | 6000 mAh | |
| Charging | 67W | 90W | |
| Wireless charging | 0W | 50W | |
| DXOMark (camera) | — | 159 | |
| Main camera | 48 MP | 50 MP | |
| Ultrawide | 8 MP | 50 MP | |
| Telephoto | 0 MP | 50 MP | |
| Front camera | 20 MP | 32 MP | |
| RAM | 6GB / 8GB / 12GB | 16GB | |
| Storage | 128GB / 256GB | 256GB / 512GB / 1TB | |
| OS | Android 12, MIUI 13 | Android 15 / HyperOS 2 | |
| Brightness (peak) | 1300 nits | 3200 nits | |
| NFC | yes | yes | |
| Protection | — | IP68 | |
| Dimensions | 163.2×76.0×7.7 mm | 161.3×75.3×9.4 mm | |
| Weight | 195 g | 225 g | |
| Launch price | — | $999 |
Camera comparison
Redmi K40S
- Main: 48MP f/1.8
- Ultrawide: 8MP
- Front: 20MP
Xiaomi 15 Ultra
- Main: 50MP f/1.63
- Ultrawide: 50MP
- Telephoto: 50MP
- Front: 32MP
Display comparison
Redmi K40S
- 6.7" AMOLED
- Resolution: 1080x2400
- Refresh rate: 120 Hz
Xiaomi 15 Ultra
- 6.7" LTPO AMOLED
- Resolution: 3200x1440
- Refresh rate: 120 Hz
Battery and charging
Redmi K40S
- 4500 mAh
- Wired: 67W
- No wireless charging
Xiaomi 15 Ultra
- 6000 mAh
- NanoReview test: web browsing 12:19 hrs, total 30:03 hrs
- Wired: 90W
- Wireless: 50W
Overall performance score
We compared Redmi K40S and Xiaomi 15 Ultra, covering their specs and all relevant benchmarks.
Xiaomi 15 Ultra leads Redmi K40S by 66.7% in our overall performance rating.
Benchmarks
Launch prices and where to check today's
Redmi K40S
Price unknownDetailed category analysis
performance
In the "performance" category, the Xiaomi 15 Ultra significantly outperforms the Redmi K40S (92/100 vs 61/100).
display
In the "display" category, the Xiaomi 15 Ultra is a bit better (90/100 vs 79/100).
camera
In the "camera" category, the Xiaomi 15 Ultra significantly outperforms the Redmi K40S (87/100 vs 36/100).
battery
In the "battery" category, the Xiaomi 15 Ultra significantly outperforms the Redmi K40S (80/100 vs 42/100).
portability
In the "portability" category, the Redmi K40S significantly outperforms the Xiaomi 15 Ultra (65/100 vs 29/100).
Frequently asked questions
Which is better: the Redmi K40S or the Xiaomi 15 Ultra?
The Xiaomi 15 Ultra significantly outperforms the Redmi K40S by 31 points (85/100 vs 54/100).
What is the rating of the Redmi K40S and the Xiaomi 15 Ultra?
The Redmi K40S has a MobileRank rating of 54/100, the Xiaomi 15 Ultra — 85/100.
Which has the better camera: the Redmi K40S or the Xiaomi 15 Ultra?
The Xiaomi 15 Ultra leads on camera score (87/100 vs 36/100).
Which is more powerful: the Redmi K40S or the Xiaomi 15 Ultra?
The Xiaomi 15 Ultra leads on performance (92/100 vs 61/100).
Should you choose the Redmi K40S over the Xiaomi 15 Ultra?
The Redmi K40S is a better fit for active users. The Xiaomi 15 Ultra is a better fit for gamers and power users, mobile photography enthusiasts, those who care about battery life, budget-conscious buyers.