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Xiaomi Redmi K40, picture 1
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Phone

Xiaomi Redmi K40

Brand
Xiaomi
Release date
Mar 1, 2021
Screen size
6.67 ″
Chip
Snapdragon 870
Memory
12 GB
Storage
128 GB

The UnboxingTN Verdict

out of 100

The Redmi K40 combines strong performance, 5G connectivity and a smooth display, but its battery and Android 11 hold it back.

What is good

  • Snapdragon 870 delivers strong everyday and gaming performance.
  • 6.67-inch 120Hz AMOLED display offers fluid visuals.
  • 5G, Wi-Fi 6 and NFC provide excellent connectivity.

What is not

  • The 4520 mAh battery is a notable weakness.
  • 33W charging is modest.
  • Android 11 is an aging software version.

How the score breaks down

  • Performance 70
  • Camera 71
  • Display 72
  • Battery 21
  • Connectivity 91
  • Build 55
  • Software 34

UnboxingTN review · based on the specifications · engine 1.0.2 · Updated Sep 13, 2026

Written by UnboxingTN’s AI from the score and the specification sheet.

Reader reviews are coming, beside this score and never blended into it.

Also known as

redmi-k40

Specifications

Performance

Chip
Snapdragon 870
Chip maker
Qualcomm
Process
7 nm
Graphics
Adreno 650
Operating system
Android
System version
11

Memory and storage

Memory
12 GB
Storage
128 GB
256 GB

Display

Screen size
6.67 ″
Resolution
1,080 × 2,400
Panel type
AM-OLED
Refresh rate
120 Hz
Pixel density
395 ppi

Battery

Battery
4,520 mAh
Wired charging
33 W

Cameras

Cameras
main · 48 MP
selfie · 19.7 MP

Connectivity

Mobile network
5G
Wi-Fi
WiFi 6
Bluetooth
Bluetooth 5.1
NFC
Yes
USB
USB C reversible

Design

Weight
196 g
Height
163.7 mm
Width
76.4 mm
Thickness
7.8 mm

Data source · techapi:redmi-k40