List of All the File Extensions Formats and Types Starting With the Letter R
| File Extension | Description |
| .RAR | WinRAR compressed archive Java JCA Resource Adapter module |
| .RAW | RAW image format CD/DVD image HP V41 program ISIS RAW file format Nicolet Summit DaStar data Nimbus 7 data RAW audio format Sentry 2020 encryption ZX Spectrum memory dump |
| .RECORD | GarageBand Records recorded music |
| .REFERENCE | Budget In Brief application reference |
| .REGI | Kagi Registration Module |
| .RELS | Microsoft Open Office XML relationships |
| .RESMONCFG | Microsoft Windows Resource Monitor settings |
| .REW | MRMC Markov Reward Model Checker definition |
| .REWI | MRMC Markov Reward Model Checker definition |
| .REZ | Alien vs Predator game Escape Velocity Nova plugin LithTech game engine resource Resume Divider |
| .RMVB | RealMedia variable bitrate |
| .RPT | Report Sage MAS 90 data Sierra Mastercook cookbook Systems Management Server (SMS) replication TrueNet Print template |
| .RUBY | Ruby Software |
| .RUJ | Oracle Recovery-Unit Journal format |
| .RULESET | Microsoft Visual Studio Code Analysis ruleset |
| .RUM | Bink video subtitle |