Redmi K90 Ultra vs Samsung Galaxy A21s
The Redmi K90 Ultra (2026) runs on the Qualcomm Snapdragon 8 Elite, while the Samsung Galaxy A21s (2020) runs on the Exynos 850; launch prices were $420 and $215. By overall MobileRank rating, the Redmi K90 Ultra leads — 73/100 vs 29/100 (a 44-point difference). Key differences: the Redmi K90 Ultra has the bigger battery (8550 mAh vs 5000); the main camera is 50 MP vs 48 MP; the Redmi K90 Ultra is faster in AnTuTu (3,233,695 vs 234,339); the Samsung Galaxy A21s is noticeably lighter (192g vs 227g).
Profile comparison
Category scores
Redmi K90 Ultra
Samsung Galaxy A21s
What makes Redmi K90 Ultra better?
- Higher AnTuTu: 3233695 vs 234339
- Better Geekbench Single: 3013 vs 300
- Better Geekbench Multi: 9287 vs 836
- Bigger battery: 8550 vs 5000 mAh
- Better main camera: 50MP vs 48MP
- Higher refresh rate: 165Hz vs 60Hz
- Higher performance (92/100 vs 16/100)
- Better camera (37/100 vs 30/100)
- Longer battery life (78/100 vs 52/100)
- Better display (94/100 vs 32/100)
What makes Samsung Galaxy A21s better?
- Lighter: 192g vs 227g
- Cheaper at launch: $215 vs $420
- Better portability (55/100 vs 40/100)
Comparison verdict
Comparing the Redmi K90 Ultra vs the Samsung Galaxy A21s, the Redmi K90 Ultra scores 44 points higher (73/100 vs 29/100). In the "performance" category, the Redmi K90 Ultra leads (92/100 vs 16/100). In the "battery" category, the Redmi K90 Ultra leads (78/100 vs 52/100). Value score: Redmi K90 Ultra — 72/100, Samsung Galaxy A21s — 16/100; it shows how far a model sits above or below the usual level for its price, and is not part of the overall rating. In the "performance" category, the Redmi K90 Ultra significantly outperforms the Samsung Galaxy A21s (92/100 vs 16/100). In the "display" category, the Redmi K90 Ultra significantly outperforms the Samsung Galaxy A21s (94/100 vs 32/100). In the "camera" category, the Redmi K90 Ultra is a bit better (37/100 vs 30/100). In the "battery" category, the Redmi K90 Ultra notably outperforms the Samsung Galaxy A21s (78/100 vs 52/100). In the "portability" category, the Samsung Galaxy A21s notably outperforms the Redmi K90 Ultra (55/100 vs 40/100).
Specs comparison
| Specification | Redmi K90 Ultra | Samsung Galaxy A21s | |
|---|---|---|---|
| Processor | Qualcomm Snapdragon 8 Elite | Exynos 850 | |
| AnTuTu | 3233695 | 234339 | |
| Geekbench Single | 3013 | 300 | |
| Geekbench Multi | 9287 | 836 | |
| Display | 6.8" AMOLED | 6.5" IPS LCD | |
| Resolution | 1280x2772 | — | |
| Refresh rate | 165 Hz | 60 Hz | |
| Battery | 8550 mAh | 5000 mAh | |
| Charging | 100W | — | |
| Main camera | 50 MP | 48 MP | |
| Ultrawide | 8 MP | 0 MP | |
| Front camera | 20 MP | 13 MP | |
| RAM | 12GB / 16GB | 3GB / 4GB / 6GB | |
| Storage | 256GB / 512GB | 32GB / 64GB | |
| OS | Android 16 | — | |
| Brightness (peak) | 3500 nits | — | |
| NFC | yes | yes | |
| Protection | IP68/IP69 | — | |
| Dimensions | 162.9×77.9×8.2 mm | 163.7×75.3×8.9 mm | |
| Weight | 227 g | 192 g | |
| Launch price | $420 | $215 |
Camera comparison
Redmi K90 Ultra
- Main: 50MP f/1.7
- Ultrawide: 8MP
- Front: 20MP
Samsung Galaxy A21s
- Main: 48MP
- Front: 13MP
Display comparison
Redmi K90 Ultra
- 6.8" AMOLED
- Resolution: 1280x2772
- Refresh rate: 165 Hz
Samsung Galaxy A21s
- 6.5" IPS LCD
- Refresh rate: 60 Hz
Battery and charging
Redmi K90 Ultra
- 8550 mAh
- Wired: 100W
- No wireless charging
Samsung Galaxy A21s
- 5000 mAh
- No wireless charging
Overall performance score
We compared Redmi K90 Ultra and Samsung Galaxy A21s, covering their specs and all relevant benchmarks.
Redmi K90 Ultra leads Samsung Galaxy A21s by 1279.9% in our overall performance rating.
Benchmarks
Launch prices and where to check today's
Launch price difference: $205. Samsung Galaxy A21s was $205 cheaper at launch.
Detailed category analysis
performance
In the "performance" category, the Redmi K90 Ultra significantly outperforms the Samsung Galaxy A21s (92/100 vs 16/100).
display
In the "display" category, the Redmi K90 Ultra significantly outperforms the Samsung Galaxy A21s (94/100 vs 32/100).
camera
In the "camera" category, the Redmi K90 Ultra is a bit better (37/100 vs 30/100).
battery
In the "battery" category, the Redmi K90 Ultra notably outperforms the Samsung Galaxy A21s (78/100 vs 52/100).
portability
In the "portability" category, the Samsung Galaxy A21s notably outperforms the Redmi K90 Ultra (55/100 vs 40/100).
Frequently asked questions
Which is better: the Redmi K90 Ultra or the Samsung Galaxy A21s?
The Redmi K90 Ultra significantly outperforms the Samsung Galaxy A21s by 44 points (73/100 vs 29/100).
What is the rating of the Redmi K90 Ultra and the Samsung Galaxy A21s?
The Redmi K90 Ultra has a MobileRank rating of 73/100, the Samsung Galaxy A21s — 29/100.
Which has the better camera: the Redmi K90 Ultra or the Samsung Galaxy A21s?
The Redmi K90 Ultra leads on camera score (37/100 vs 30/100).
Which is more powerful: the Redmi K90 Ultra or the Samsung Galaxy A21s?
The Redmi K90 Ultra leads on performance (92/100 vs 16/100).
Should you choose the Redmi K90 Ultra over the Samsung Galaxy A21s?
The Redmi K90 Ultra is a better fit for gamers and power users, those who care about battery life.