| Hardware and OS | BLU S91 | |
| Operating system | Android 11 | |
| Processor | Octa-core (4x2.0 GHz Cortex-A53 & 4x1.5 GHz Cortex-A53) | |
| Chipset | MediaTek MT6762G Helio G25 (12 nm) | |
| Internal memory | 128GB 4GB RAM | |
| External memory | microSDXC | |
| GPU | PowerVR GE8320 | |
| Display | BLU S91 | other phones |
| Type | IPS LCD | |
| Size | 6.5" inc | |
| Resolution | 720 x 1600 px | |
| Display colors | 16M | |
| Screen area | 102.0 cm2 | |
| Screen format | 20:9 (height:width) | |
| Screen to body ratio | 81.1% | |
| PPI /points per inch/ | 270 PPI | |
| Touchscreen | capacitive touchscreen | |
| Connectivity | BLU S91 | other phones |
| Network | GSM / HSPA / LTE | |
| NFC | No | |
| Edge | Yes | |
| Bluetooth | 5.0, A2DP, LE | |
| SIM card | Dual SIM (Nano-SIM, dual stand-by) | |
| GPRS | Yes | |
| GPS | Yes, with A-GPS | |
| Wi-Fi | Wi-Fi 802.11 a/b/g/n, Wi-Fi Direct, hotspot | |
| USB | USB Type-C 2.0, USB On-The-Go | |
| Camera | BLU S91 | other phones |
| Rear camera, main | 13 MP, Triple | |
| Camera specs | 13 MP, (wide), PDAF
-0.3 MP, f/2.4, (macro)
-0.3 MP, f/2.4, (depth) | |
| Functions | LED flash, HDR, panorama | |
| Video | 1080p@30fps | |
| Front camera, selfie | 13 MP, Single | |
| Multimedia | BLU S91 | other phones |
| Headphone jack | Yes | |
| Radio | FM radio | |
| Design | BLU S91 | other phones |
| Dimensions (HxWxD) | 164.8 x 76.3 x 8.9 mm | 6.49 x 3 x 0.35 in | |
| Weight | 202 g | 7.13 oz | |
| Colors | Black, Green | |
| Battery | BLU S91 | other phones |
| Battery | 5000 mAh, Li-Po, non-removable | |
| Other features | BLU S91 | other phones |
| Sensors | Fingerprint (rear-mounted), accelerometer, gyro, proximity, compass | |
