| Hardware and OS | Karbonn A40 Indian | Oppo A3s |
| Operating system | Android 7.0 Nougat | Android 8.1 (Oreo); ColorOS 5.1 |
| Processor | Quad-Core 1.3GHz Cortex-A7 | Octa-core 1.8 GHz Cortex-A53 |
| Chipset | | Qualcomm SDM450 Snapdragon 450 (14 nm) |
| GPU | ARM Mali-400 MP2, 4-Cores | Adreno 506 |
| RAM | 1GB | |
| Internal memory | | 16 GB, 2 GB RAM |
| Internal Storage | 8GB | |
| External memory | | microSD, up to 256 GB (dedicated slot) |
| Memory Card Slot | microSD, microSDHC, microSDXC | |
| User Interface | Yes with Modified Android | |
| Display | Karbonn A40 Indian | Oppo A3s |
| Type | TFT capacitive touchscreen | IPS LCD |
| Size | 4.0 inches | 6.2" inc |
| Resolution | 480 x 800 Pixels, 24 bit color depth | 720 x 1520 px |
| Touchscreen | Yes Multi Touch Support | capacitive touchscreen |
| Screen-to-Body Ratio | | 81.2% |
| Display area | | 95.9 cm2 |
| Display aspect ratio | | 19:9 (height:width) |
| Pixel Density | ~ 233 PPI | 271 PPI |
| Protection | None | |
| Colors | 16M Colors | 16M |
| Features | WVGA display, ~ 233 PPI, Capacitive, Multi-touch, 2.5D curved glass screen, Corning Gorilla Glass, 400 nits Brightness, In-Cell Touch | |
| Connectivity | Karbonn A40 Indian | Oppo A3s |
| 2G Network | | GSM 850 / 900 / 1800 / 1900 - SIM 1 & SIM 2 |
| 3G Network | | HSDPA 850 / 900 / 2100 |
| 4G Network | Yes | LTE |
| Wi-Fi | Wi-Fi 802.11 a/b/g/n, Wi-Fi Hotspot | Wi-Fi 802.11 b/g/n, WiFi Direct, hotspot |
| NFC | No | |
| Network | | GSM / HSPA / LTE |
| SIM card | | Dual SIM (Nano-SIM, dual stand-by) |
| Bluetooth | | 4.2, A2DP, LE |
| SIM | Micro SIM | |
| Edge | | Yes |
| Dual SIM | Dual SIM (Micro, Micro) | |
| GPRS | | Yes |
| Wireless Charging | No | |
| GPS | Yes, with GPS, A-GPS | Yes, with A-GPS |
| Speed | LTE : 850 / 1800 MHz LTE-TDD : 2300 MHz (Band 40) | HSPA 42.2/5.76 Mbps, LTE-A (2CA) Cat6 300/50 Mbps |
| USB | Micro USBv2.0, With Charging and Mass Storage Function | microUSB 2.0, USB On-The-Go |
| Camera | Karbonn A40 Indian | Oppo A3s |
| Image | 1600 x 1200 Pixels | |
| Main camera | 2 Megapixels | 13 MP, Dual |
| Specs | | 13 MP, f/2.2, AF
-2 MP, f/2.4, depth sensor |
| Features | Yes with Single-LED Flash | LED flash, HDR, panorama |
| Video | | 1080p@30fps |
| Selfie camera | VGA | 8 MP, Single |
| Multimedia | Karbonn A40 Indian | Oppo A3s |
| Loudspeaker | Yes | |
| Handsfree | Yes | |
| Video Playback | Yes Support 3GP, MP4, xVID, AVI, H.264, H.263 | |
| Video Out | Not Support | |
| 3.5 mm Jack | yes | Yes |
| Ring Tones | Yes | |
| Radio | Yes | FM radio |
| Design | Karbonn A40 Indian | Oppo A3s |
| Colors | | Red, Dark Purple |
| Dimensions | 122.95 mm x 64.3 mm x 10.5 mm | 156.2 x 75.6 x 8.2 mm |
| Waterproof | No | |
| Weight | 118 Grams (Without Battery) | 168 g |
| Battery | Karbonn A40 Indian | Oppo A3s |
| Battery capacity | | 4230 mAh, Non-removable Li-Ion |
| Capacity | 1,400 mAh Lithium-Ion | |
| Placement | Removable | |
| Other | Karbonn A40 Indian | Oppo A3s |
| Release date | | 2018, July |
| Sensors | Accelerometer | Accelerometer, proximity, compass |
