| Extension | Summary |
|---|
| .R | REBOL Script |
| .R0 | WinRAR Compressed Archive |
| .R00 | WinRAR Compressed Archive |
| .R01 | WinRAR Split Archive Part 1 |
| .R02 | WinRAR Split Archive Part 2 |
| .R03 | WinRAR Split Archive Part 3 |
| .R04 | WinRAR Split Archive Part 4 |
| .R1 | WinRAR Multi-Volume Archive Part 1 |
| .R1M | RealOne Streaming Media File |
| .R2 | WinRAR Multi-Volume Archive Part 2 |
| .R21 | WinRAR Split Archive Part 21 |
| .R2D | Borland Reflex Database |
| .R30 | WinRAR Split Archive Part 30 |
| .R3D | RISA-3D Model File |
| .R3PROJ | RPG Maker 2003 Project |
| .R5A | 7ev3n Ransomware Encrypted File |
| .RA | RealAudio File |
| .RAD | Citrix Rapid Application Delivery File |
| .RADIUMKEY2 | Radium 2 License File |
| .RADQ | Need for Madness Game Archive |
| .RAF | Fuji RAW Image File |
| .RAL | WinRail Track Design File |
| .RAM | Real Audio Metadata File |
| .RAP | Scarab Ransomware Encrypted File |
| .RAR | WinRAR Compressed Archive |
| .RAS | Remedy Archive System File |
| .RASI | Rofi Configuration File |
| .RASKINLICENSE | Raskin License File |
| .RASKINPLACE | Raskin Place Layout File |
| .RASUNSOFT | Rasunsoft Game Replay File |
| .RAT | PICS Rating File |
| .RATDVD | RatDVD Disk Image |
| .RAV | Rave Reports Project File |
| .RAVI | Radiometric Video File |
| .RAW | Dolphin Wii and Gamecube Emulator Game Save File |
| .RAX | Real Music Store Audio File |
| .RAY | Rayshade Image |
| .RB | Real Studio Project |
| .RB4 | RobotWorks Parameters File |
| .RBC | Retrospect Backup Catalog File |
| .RBF | Retrospect Backup File |
| .RBJ | XRK Compiled Redcode Object File |
| .RBK | Windows 95 Registry Backup File |
| .RBM | Real Studio Menu File |
| .RBP | Real Studio Project File |
| .RBS | Windows Installer Rollback Script |
| .RBT | LEGO MINDSTORMS NXT Program |
| .RBVCP | Real Studio Version Controlled Project |
| .RBW | Real Studio Window File |
| .RBX | Rembo-C Compiled Script |
| .RBXL | Roblox Location File |
| .RBXLX | Roblox XML Place File |
| .RBXM | Roblox Model |
| .RBXMX | Roblox Model |
| .RBXS | Roblox Script |
| .RBZ | SketchUp Plugin |
| .RC | Resource Script |
| .RC1 | Samsung Mobile Device Firmware File |
| .RC2 | Visual Studio Resources File |
| .RCC | Recap Compressed Structured Scan Data File |
| .RCD | LEGO MINDSTORMS Recording File |
| .RCF | SonicWALL VPN Configuration File |
| .RCG | Recog Character Recognition Set |
| .RCL | Easy CD and DVD Creator 6 Project |
| .RCM | Autodesk Reality Capture Mesh |
| .RCO | PlayStation Portable Resource File |
| .RCPROJECT | Apple Reality Composer Project |
| .RCREC | LogMeIn Remote Control Session Recording |
| .RCS | RandomControl Scene File |
| .RCT | Visual Studio Resource Template |
| .RCTD | RabbitCT Dataset |
| .RCU | RealWorld Layered Cursor Image |
| .RCUT | Webinaria Recording Cut |
| .RCV | BIOS Recovery File |
| .RCX | REDCINE-X Project File |
| .RCY | ReCycle 1.x Document |
| .RDA | Anno 2070 Data File |
| .RDATA | R Workspace File |
| .RDB | Retrospect Backup Set |
| .RDC | IDRISI Raster Documentation File |
| .RDF | PowerProducer Disc Image |
| .RDG | RDCman Config File |
| .RDI | Rohos Disk Image File |
| .RDL | MicroStation Redline File |
| .RDLC | Visual Studio Client Report Definition File |
| .RDLX | Power View Project File |
| .RDO | Xerox Rawster Document Object File |
| .RDOC | Ruby Document |
| .RDOC_OPTIONS | Ruby Document Options File |
| .RDP | Remote Desktop Configuration File |
| .RDR | Remote Desktop Manager Report Settings File |
| .RDS | Ray Dream Studio Scene File |
| .RDW | Real-DRAW Project File |
| .RDX | Reflex Data File |
| .README | Readme File |
| .REAL | Aero Experience |
| .REALITY | Reality 3D Scene Format |
| .REB | REBOL Script File |
| .REC | Topfield PVR Recording |
| .RECORD | GarageBand Records Audio File |
| .RED | Red Source Code File |
| .REDIF | ReDIF Template |
| .REDIR | Spotify Executable Redirect File |
| .REDS | Red/System Source Code File |
| .REF | IDRISI Raster Image Reference File |
| .REFERENCE | Budget In Brief Reference File |
| .REFRESH | Visual Studio Refresh File |
| .REG | Registration Information File |
| .REGLNK | Registry Editor Shortcut File |
| .REGTRANS-MS | Registry Transaction Log File |
| .REL | Relocatable Module File |
| .RELOC | Windows EXE Relocation Section File |
| .RELS | Open Office XML Relationships File |
| .REM | BlackBerry Encrypted Data File |
| .REP | StarCraft Replay File |
| .REPEAKS | REAPER Peak File |
| .REPLAY | Rocket League Replay File |
| .REPP | Repp Ransomware Encrypted File |
| .REQ | SSL Certificate Request File |
| .RES | Godot Engine Resource File |
| .RESJSON | Windows JavaScript Resources File |
| .RESMONCFG | Resource Monitor Configuration File |
| .RESOURCES | Visual Studio Resource File |
| .RESS | Unity 3D Model Archive |
| .RESW | Windows Resources File |
| .RESX | .NET Managed Resources File |
| .RET | BusinessObjects Template |
| .REV | RAR Recovery Volume Set |
| .REX | Rexx Source File |
| .REXX | Rexx Source File |
| .REZ | Escape Velocity Plug-in File |
| .RF1 | Retirement Forecast File |
| .RFA | Battlefield 1942 Game Package |
| .RFB | RoboForm Bookmark File |
| .RFC | RoboForm Contact File |
| .RFD | Emperor: Battle for Dune Data File |
| .RFGS_PC | Red Faction: Guerilla Saved Game File |
| .RFL | Ravenfield Map |
| .RFLW | Edge Reflow Data File |
| .RFM | rFactor Modification File |
| .RFN | RoboForm Safenote File |
| .RFO | RoboForm Option File |
| .RFP | RoboForm Passcard File |
| .RFQ | RoboForm SearchCard File |
| .RFT | RoboForm Identity File |
| .RFU | Remote Firmware Update |
| .RFW | Rockchip Firmware File |
| .RGB | Q0 Image File |
| .RGBA | RGB Bitmap |
| .RGD | Raft Saved Game File |
| .RGE | Entourage File Archive |
| .RGF | LEGO MINDSTORMS EV3 Robot Graphics File |
| .RGN | Garmin Regional Map File |
| .RGO | RepliGo File |
| .RGP | RealArcade Game Package |
| .RGRID | RepGrid File |
| .RGRP | Pro Tools Region Group File |
| .RGS | Registry Script |
| .RGSS2A | RPG Maker VX RGSS Encrypted Archive |
| .RGSS3A | RPG Maker VX Ace RGSS Encrypted Archive |
| .RGSSAD | RPG Maker VX RGSS Encrypted Archive |
| .RGT | Relic Entertainment Game Texture File |
| .RHISTORY | R History File |
| .RHP | Rhino Plug-in |
| .RHR | Script Rehearser Script File |
| .RHTML | Ruby HTML Web Page |
| .RIC | NXT Image File |
| .RIDL | RIDL Type Library File |
| .RIF | Painter Raster Image File |
| .RIFF | Painter Raster Image |
| .RIG | vRigger Design File |
| .RIM | BioWare Resource Image File |
| .RIP | Hit'n'Mix Audio Mashup File |
| .RIS | Research Information Systems Citation File |
| .RISE | RISE Editor Model File |
| .RIX | ColoRIX Image |
| .RJS | RealJukebox Skin File |
| .RK | WinRK File Archive |
| .RKG | Mario Kart Wii Time Trial Ghost |
| .RKP | Rockchip MP4 Player Game |
| .RKT | Racket Source Code File |
| .RL | The 7th Guest Audio Data File |
| .RLE | Golly Simulation Pattern File |
| .RLE.GZ | Golly Compressed Simulation Pattern File |
| .RLF | ArcGIS Report Layout File |
| .RLI | RealWorld Graphics Layered Image |
| .RLL | Microsoft Resource Library |
| .RLS | Symbian Localization File |
| .RM | RealMedia File |
| .RMA | Rhapsody DRM License Data File |
| .RMBAK | Registry Mechanic Backup File |
| .RMD | RED Metadata File |
| .RMF | Adobe Rights Management Document |
| .RMGB | RootsMagic Backup File |
| .RMGC | RootsMagic Data File |
| .RMH | Rights-Managed HTML Document |
| .RMI | RMID MIDI File |
| .RMJ | Real Media Jukebox Audio File |
| .RML | Redline Markup Language Format |
| .RMM | RAM Meta File |
| .RMP | Magellan Raster Map File |
| .RMR | ResumeMaker File |
| .RMS | Java Application Settings File |
| .RMSKIN | Rainmeter Skin File |
| .RMT | Router Firmware File |
| .RMUF | Alpha Five Runtime License File |
| .RMVB | RealMedia Variable Bit Rate File |
| .RMX | RealJukebox Format |
| .RNC | RELAX NG Compact Syntax File |
| .RND | Random Hash Data File |
| .RNG | Nokia Composer Ringtone |
| .RNQ | Renque Model File |
| .RNS | Reason Song File |
| .RNX | RealPlayer Settings File |
| .ROADTRIP | Road Trip Planner File |
| .ROCA | RIB office Compressed Archive |
| .ROCK | Rockbox Plug-in |
| .ROD | Ancestry Genealogical Database File |
| .RODL | RemObjects Definition Language File |
| .RODX | Ancestry Genealogical Database File |
| .RODZ | Ancestry Genealogical Database File |
| .ROFL | League of Legends Replay File |
| .ROG | Roger 2 Input Data File |
| .ROI | Shark Sales System Data File |
| .ROL | Ad Lib Synthesized Instrument |
| .ROM | Read Only Memory Image |
| .ROQ | Id Software Game Video |
| .ROS | BattleScribe Roster Editor File |
| .ROT | Homeworld 2 Graphics File |
| .ROTEST | RemObjects SDK Test File |
| .ROTESTRESULT | RemObjects SDK Test Results File |
| .ROU | Gerber Route File |
| .ROV | Report Object Variable |
| .ROX | Actuate Report Object Executable File |
| .ROXIO | Roxio Project |
| .ROZ | aSc TimeTables Schedule File |
| .RP | RealPix Clip |
| .RP2 | RetroPlatform Player Program Archive |
| .RP9 | RetroPlatform Disk Image Archive |
| .RPA | Ren'Py Archive |
| .RPB | Radmin Phonebook File |
| .RPC | Rich Page Content Document |
| .RPD | RIB Project Database File |
| .RPE | OPC Router Configuration 4 Project |
| .RPF | Grand Theft Auto Data File |
| .RPGMVM | RPG Maker MV Encrypted M4A File |
| .RPGMVO | RPG Maker MV Encrypted OGG File |
| .RPGMVP | RPG Maker MV Encrypted PNG File |
| .RPGPROJECT | RPG Maker MV Project |
| .RPGSAVE | RPG Maker MV Save File |
| .RPI | Render Plug-in |
| .RPJ | Real Pac Batch Job File |
| .RPK | RadLight Media Player Skin |
| .RPKG | Hitman Game Patch Archive |
| .RPL | Special Force Replay |
| .RPLIB | Axure RP Widget Library File |
| .RPLN | InDesign Required Plug-in File |
| .RPM | Red Hat Package Manager File |
| .RPMNEW | Red Hat Package New Default Configuration |
| .RPMSAVE | Red Hat Package Saved Configuration |
| .RPMSG | Outlook Restricted Permission Message |
| .RPP | REAPER Project File |
| .RPPRJ | Axure RP Shared Project File |
| .RPRES | R Presentation File |
| .RPROJ | R Project |
| .RPS | 3ds Max Render Preset Settings |
| .RPT | AccountEdge Report |
| .RPTR | RafflePrinter Document |
| .RPV | RealPlayer Visualization File |
| .RPX | Wii U Game |
| .RPY | Python Script |
| .RPYB | Ren'Py Bytecode File |
| .RPYC | Ren'Py Compiled Script |
| .RRA | vRigger Rigging Gear File |
| .RRD | Reduced Resolution Dataset File |
| .RRI | RealWorld Image |
| .RRR | Registry Mechanic Backup File |
| .RRT | Rhapzode Resource Template |
| .RS | Rust Source Code File |
| .RS2 | RailSim2 Saved Layout File |
| .RSA | Minecraft JAR Codesign File |
| .RSB | PopCap Resource Stream Binary File |
| .RSC | Symbian Application Compiled Resource File |
| .RSCOLLECTION | RetroShare Collection |
| .RSD | RealSQLDatabase File |
| .RSDF | RapidShare Download File |
| .RSDK | Retro SDK Archive |
| .RSF | LEGO MINDSTORMS EV3 Robot Sound File |
| .RSG | RaySupreme Graph |
| .RSM | RouterSim Network Visualizer File |
| .RSN | Reason Project File |
| .RSO | NXT Brick Audio File |
| .RSP | C# Compiler Response File |
| .RSR | Poser Model Preview File |
| .RSRC | Macintosh Resource File |
| .RSS | Symbian Application Resource File |
| .RST | IDRISI Raster Image |
| .RSV | RSView32 Project File |
| .RSW | R&R SQL Report Writer Report File |
| .RSX | RED Metadata XML File |
| .RT | RealText Streaming Text File |
| .RTA | TrueRTA Project File |
| .RTC | Live Meeting Connection File |
| .RTD | Robot Structural Analysis Design File |
| .RTE | RTE Encoded File |
| .RTF | Rich Text Format File |
| .RTFD | Rich Text Format Directory File |
| .RTI | Raster Music Tracker Instrument File |
| .RTL | Raster Transfer Language File |
| .RTM | LabVIEW Run-Time Menu File |
| .RTON | PopCap Games Data File |
| .RTP | TurboTax Update File |
| .RTS | Royal TS Remote Connection File |
| .RTSTN | Audials Station File |
| .RTTEX | Robinson Technologies Texture File |
| .RTTTL | Ring Tone Transfer Language File |
| .RTWSH | Radiotracker Wishlist File |
| .RTX | Rich Text Document |
| .RU | Java Russian Font Properties File |
| .RUEL | Revo Uninstaller Pro Log |
| .RUF | Samsung DVD and Blu-ray Player Firmware File |
| .RUL | InstallShield Rules File |
| .RULESET | Visual Studio Code Analysis Rule Set File |
| .RUM | Bink Video Subtitle File |
| .RUN | Rune Map File |
| .RUPAF | Revo Uninstaller Pro Activation File |
| .RV | RealVideo File |
| .RVDATA | RPG Maker VX Data File |
| .RVDATA2 | RPG Maker VX Ace Data File |
| .RVF | RichView Format File |
| .RVG | RVG X-ray Image |
| .RVID | Snapz Pro X Recorded Video File |
| .RVL | muvee Reveal X Project File |
| .RVP | Sharp Blu-ray Player Firmware File |
| .RVPROJ | RPG Maker VX Project File |
| .RVPROJ2 | RPG Maker VX Ace Project File |
| .RVT | Revit Project File |
| .RVX | Real Protected Video File |
| .RVZ | Compressed Wii / GameCube ROM |
| .RW2 | Panasonic RAW Image |
| .RW3 | RapidWeaver 3 Site File |
| .RWD | Microsoft Flight Simulator Rewards File |
| .RWG | Random Word Generator Project File |
| .RWL | Leica RAW Image |
| .RWLIBRARY | Paperless Receipt Library |
| .RWP | RapidWeaver Package |
| .RWPLUGIN | RapidWeaver Plugin |
| .RWS | RenderWare Stream File |
| .RWSNIPPET | RapidWeaver Snippet File |
| .RWSTYLE | RapidWeaver Style File |
| .RWSW | RapidWeaver Site File |
| .RWT | ReadWriteThink Printing Press Draft |
| .RWTHEME | RapidWeaver Theme |
| .RWZ | Outlook Rules Wizard File |
| .RX2 | REX2 Audio File |
| .RXC | Roxio Certificate File |
| .RXDATA | RMXP Data File |
| .RXE | Lego Mindstorms NXT Executable Program |
| .RZ | Rzip Compressed File |
| .RZB | Red Zion Book File |
| .RZK | Red Zion Key File |
| .RZN | Red Zion Notes File |
| .RZS | Red Zion Security File |
| .RZX | File Crypt Encrypted File |