| Local Name | Redmi K40 |
| Technology | GSM / CDMA / HSPA / CDMA2000 / LTE / 5G |
| 4G Bands | 1, 2, 3, 4, 5, 7, 8, 18, 19, 26, 28, 34, 38, 39, 40, 41, 42 |
| 3G Bands | HSDPA 850 / 900 / 1700(AWS) / 1900 / 2100 | CDMA2000 1x |
| 2G Bands | GSM 850 / 900 / 1800 / 1900 - SIM 1 & SIM 2 | CDMA 800 |
| Speed | HSPA 42.2/5.76 Mbps, LTE-A, 5G |
| Announced | 2021, February 25 |
| Status | Available. Released 2021, March 04 |
| Dimensions | 163.7 x 76.4 x 7.8 mm (6.44 x 3.01 x 0.31 in) |
| Weight | 196 g (6.91 oz) |
| SIM | Dual SIM (Nano-SIM, dual stand-by) |
| Display Type | Li-Po 4520 mAh, non-removable |
| Screen Size | 6.67 inches, 107.4 cm2 (~85.9% screen-to-body ratio) |
| Resolution | 1080 x 2400 pixels, 20:9 ratio (~395 ppi density) |
| Protection | Corning Gorilla Glass 5 |
| OS | Android 11, MIUI 12 |
| Chipset | Qualcomm SM8250-AC Snapdragon 870 5G (7 nm) |
| CPU | Octa-core (1x3.2 GHz Kryo 585 & 3x2.42 GHz Kryo 585 & 4x1.80 GHz Kryo 585) |
| GPU | Adreno 650 |
| Card Slot | No |
| Internal Memory | 128GB 6GB RAM, 128GB 8GB RAM, 256GB 8GB RAM, 256GB 12GB RAM | UFS 3.1 |
| Camera Features | HDR |
| Video | 1080p@30fps, 720p@120fps |
| Loudspeaker | Yes, with stereo speakers |
| 3.5mm Jack | No |
| Sound | 24-bit/192kHz audio |
| WLAN | Wi-Fi 802.11 a/b/g/n/ac/6, dual-band, Wi-Fi Direct, hotspot |
| Bluetooth | 5.1, A2DP, LE |
| GPS | Yes, with dual-band A-GPS, GLONASS, BDS, GALILEO, QZSS, NavIC |
| NFC | Yes |
| Infrared Port | Yes |
| Radio | No |
| USB | USB Type-C 2.0, USB On-The-Go |
| Sensors | Fingerprint (side-mounted), accelerometer, gyro, proximity, compass, color spectrum |
| Colors | Black, White, Aurora |
