| Hardware and OS | Redmi K40S | Oppo A3s |
| Operating system | Android 12 | Android 8.1 (Oreo); ColorOS 5.1 |
| Processor | Qualcomm Snapdragon 870 5G - 7 nm , octa-core (1x3.2 GHz Kryo 585 & 3x2.42 GHz Kryo 585 & 4x1.80 GHz Kryo 585) | Octa-core 1.8 GHz Cortex-A53 |
| Chipset | | Qualcomm SDM450 Snapdragon 450 (14 nm) |
| GPU | Adreno 650 | Adreno 506 |
| RAM | 6GB / 8GB / 12GB | |
| Internal memory | | 16 GB, 2 GB RAM |
| Internal Storage | UFS 3.1 : 128GB / 256GB | |
| External memory | | microSD, up to 256 GB (dedicated slot) |
| Memory Card Slot | No | |
| User Interface | MIUI 13 | |
| Display | Redmi K40S | Oppo A3s |
| Type | AMOLED, 120Hz | IPS LCD |
| Size | 6.67" , ~86.6% screen-to-body ratio | 6.2" inc |
| Resolution | 1080 x 2400p | 720 x 1520 px |
| Touchscreen | | capacitive touchscreen |
| Screen-to-Body Ratio | | 81.2% |
| Display area | | 95.9 cm2 |
| Protection | Corning Gorilla Glass 5 | |
| Display aspect ratio | | 19:9 (height:width) |
| Features | Brightness: 1300 nits (peak) , 20:9 aspect ratio, HDR10 | |
| Pixel Density | ~395 ppi | 271 PPI |
| Colors | | 16M |
| Connectivity | Redmi K40S | Oppo A3s |
| 5G Network | 1, 3, 5, 8, 28, 38, 40, 41, 77, 78 SA/NSA | |
| 2G Network | | GSM 850 / 900 / 1800 / 1900 - SIM 1 & SIM 2 |
| 3G Network | | HSDPA 850 / 900 / 2100 |
| 4G Network | 1, 2, 3, 4, 5, 8, 18, 19, 26, 34, 38, 39, 40, 41, 42 | LTE |
| NFC | Yes | |
| Wi-Fi | Wi-Fi 802.11 a/b/g/n/ac/6, dual-band, Wi-Fi Direct, hotspot | Wi-Fi 802.11 b/g/n, WiFi Direct, hotspot |
| Network | | GSM / HSPA / LTE |
| SIM card | | Dual SIM (Nano-SIM, dual stand-by) |
| SIM | Nano SIM | |
| Bluetooth | | 4.2, A2DP, LE |
| Dual SIM | Yes with dual stand-by | |
| Wireless Charging | No | |
| Edge | | Yes |
| GPRS | | Yes |
| GPS | A-GPS, GLONASS (1), BDS (3), GALILEO (2), QZSS (2), NavIC | Yes, with A-GPS |
| Speed | HSPA 42.2/5.76 Mbps, LTE-A, 5G | HSPA 42.2/5.76 Mbps, LTE-A (2CA) Cat6 300/50 Mbps |
| USB | Type-C 2.0, USB On-The-Go | microUSB 2.0, USB On-The-Go |
| Camera | Redmi K40S | Oppo A3s |
| Main camera | Triple: 48 MP, f/1.8, (wide), 1/2", 0.8 ?m, PDAF, OIS, 8 MP, 119 (ultrawide), 2 MP, f/2.4, (macro), HDR, panorama | 13 MP, Dual |
| Specs | | 13 MP, f/2.2, AF
-2 MP, f/2.4, depth sensor |
| Features | Dual - LED , Dual - tone | LED flash, HDR, panorama |
| Video | | 1080p@30fps |
| Selfie camera | 20 MP, (wide) | 8 MP, Single |
| Multimedia | Redmi K40S | Oppo A3s |
| Loudspeaker | Stereo speakers , 24-bit/192kHz audio | |
| 3.5 mm Jack | No | Yes |
| Radio | No | FM radio |
| Design | Redmi K40S | Oppo A3s |
| Waterproof | Splash resistant | |
| Colors | | Red, Dark Purple |
| Dimensions | 163.2 x 76 x 7.7 mm | 156.2 x 75.6 x 8.2 mm |
| Weight | 195g | 168 g |
| Battery | Redmi K40S | Oppo A3s |
| Capacity | 4500mAh Li-Po, 67W fast charging, PD 3.0, QC 3 | |
| Placement | Non-removable | |
| Battery capacity | | 4230 mAh, Non-removable Li-Ion |
| Other | Redmi K40S | Oppo A3s |
| Release date | | 2018, July |
| Sensors | Side-mounted fingerprint, accelerometer, gyro, proximity, compass, color spectrum | Accelerometer, proximity, compass |
