| Hardware and OS | Nokia Lumia 638 | |
| Operating system | Microsoft Windows Phone 8.1 | |
| Processor | Quad-core 1.2 GHz Cortex-A7 | |
| Chipset | Qualcomm Snapdragon 400 (28 nm) | |
| GPU | Adreno 305 | |
| Internal memory | 8 GB, 1 GB RAM | |
| External memory | microSD, up to 256 GB (dedicated slot) | |
| Display | Nokia Lumia 638 | other phones |
| Type | IPS LCD | |
| Size | 4.5" inc | |
| Resolution | 480 x 854 px | |
| Protection | Corning Gorilla Glass 3 | |
| Touchscreen | capacitive touchscreen | |
| Screen-to-Body Ratio | 64.6% | |
| Display area | 55.8 cm2 | |
| Display aspect ratio | 16:9 (height:width) | |
| Pixel Density | 218 PPI | |
| Colors | 16M | |
| Other | ClearBlack display | |
| Connectivity | Nokia Lumia 638 | other phones |
| 2G Network | GSM 850 / 900 / 1800 / 1900 | |
| 3G Network | HSDPA 850 / 900 / 1900 / 2100 - RM-1010 | |
| 4G Network | LTE band 3(1800), 7(2600), 38(2600), 39(1900), 40(2300), 41(2500) | |
| Wi-Fi | Wi-Fi 802.11 b/g/n, DLNA, hotspot | |
| Network | GSM / HSPA / LTE | |
| SIM card | Micro-SIM | |
| Bluetooth | 4.0, A2DP, LE/ aptX after WP8 Denim update | |
| Edge | Yes | |
| GPRS | Yes | |
| GPS | Yes, with A-GPS, GLONASS | |
| Speed | HSPA 42.2/5.76 Mbps, LTE Cat4 150/50 Mbps | |
| USB | microUSB 2.0 | |
| Camera | Nokia Lumia 638 | other phones |
| Main camera | 5 MP, Single | |
| Specs | 5 MP, 1/4', AF | |
| Features | Panorama | |
| Video | Yes | |
| Multimedia | Nokia Lumia 638 | other phones |
| 3.5 mm Jack | Yes | |
| Radio | FM radio | |
| Design | Nokia Lumia 638 | other phones |
| Colors | Black | |
| Dimensions | 129.5 x 66.7 x 9.2 mm | |
| Weight | 136 g | |
| Battery | Nokia Lumia 638 | other phones |
| Battery capacity | 1830 mAh, Removable Li-Ion | |
| Other | Nokia Lumia 638 | other phones |
| SAR | SAR EU - 1.46 W/kg (head), 0.95 W/kg (body) | |
| Release date | 2014, December | |
| Sensors | Accelerometer | |
