Lista de extensións de ficheiros

Algúns formatos ou extensións de ficheiros son os que están listados a continuación:

## 0–9 
* 000-999 Usado en antigas versións para separar ficheiros ordenados pola data de creación 
* 12M Lotus 123 97 Smartmaster file 
* 123 Lotus 123 97 file 
* 2GR and 3GR VGA Graphics driver/configuration files under Windows 
* 386 arquivo usado en plataformas 80386 ou procesadores máis recentes.
* 3DM formato do programa Rhinoceros3d. 
* 3DS formato do programa 3dstudio para as antigas versións en MS-DOS.
* 669 Composer 669, Unis Composer music mod file
* 7z 7-Zip file

## A 
* ABK Corel Draw AutoBackup 
* ACL Acelerador de teclado do Corel Draw 6
* ACM Windows Audio Compression Manager
* ACP Asistente de previsualización do Microsoft Office
* ACT Microsoft Office Assistant Actor (ficheiro) 
* ACV Drivers de son do OS/2 
* AD After Dark (screensaver)
* ADB Appointment Database (usada polo organizador HP 100LX)
* ADD Drivers utilizados no arranque do OS/2
* ADM After Dark MultiModule (screensaver)
* ADP Usado polo FaxWorks para configurar a interacción por fax ou módem 
* ADR After Dark Randomizer (screensaver)
* AFM Adobe Font Metrics 
* AF2 ABC Flowchart (ficheiro)
* AF3 ABC Flowchart (ficheiro)
* AI Adobe Illustrator (formato vectorial de deseño)
* AIFF Apple Mac AIFF (son)
* ALB JASC Image Commander
* ALL Arts & Letters Library 
* AMS Velvert Studio music module (MOD)
* ANC Canon Computer Pattern Maker (paleta de cores)
* ANI Animated Cursor (cursor animado)
* ANS ANSI (texto sen formato)
* API Application Program Interface (tipo de ficheiro usado polo Adobe Acrobat)
* APR Lotus Approach 97 
* APS Microsoft Visual C++
* ARC LH ARC versuñib abtiga de ficheiro comprimido
* ARJ Formato de ficheiro comprimido ARJ, deseñado por Robert Jung
* ART Xara Studio (deseño)
* ART Canon Crayola
* ASA Microsoft Visual InterDev 
* ASC Texto ASCII
* ASD WinWord AutoSave 
* ASM Assembler
* ASP Active Server Page (linguaxe web) 
* AST "Asistente" do Claris Works
* ATT AT&T Group 4 (mapa de bits)
* AVI Microsoft Video for Windows movie (ficheiro de vídeo)
* AWD FaxView

## B 
* BAK Backup (copia de seguranza)
* BAS BASIC
* BAT Batch
* BFC Documento "Briefcase" do Windows 95 "Briefcase"
* BG "Backgammon" for Windows game 
* BI Ficheiro en código binario
* BIG Electronic Arts Graphics File
* BIF GroupWise initialization file 
* BIN Binary file 
* BK Similar a .bak
* BK$ Similar a .bak
* BKS "Bookshelf", formato de libro electrónico deseñado pola IBM
* BLEND Exensión do Blender3D.
* BMK Ficheiro de "bookmark"
* BMP Mapa de bits para o Windows ou o OS/2
* BM1 Apogee BioMenace
* BRX Ficheiro para navegar ("browsing") e indexar opcións multimedia 
* BSP Quake map 
* BS1 Apogee Blake Stone
* BTM "Batch file" usado polo Norton Utilities 
* B4 Ficheiro para Helix Nuts e Bolts

## C 
* C Código escrito en linguaxe de programación *C* 
* CAB "Cabinet"Ficheiro de compresión de ficheiros utilzado pola Microsoft para a distribución de software
* CAL Mapa de bits comprimido CALS
* CAL Calendario
* CAS "Comma-delimited ASCII"
* CAT IntelliCharge categorization file used by Quicken 
* CB Ficheiro para "clean boot" (*limpar arranque*) de Microsoft
* CCB Configuración animada de botón en Visual Basic
* CCF Ficheiro de visor multimedia usado en OS/2 
* CCH "Corel Chart"
* CCM Lotus CC:Mail "box" (por exemplo, INBOX.CCM) 
* CDA CD Audio Track 
* CDF Microsoft Channel Definition Format
* CDI Phillips Compact Disk Interactive
* CDR Corel Draw Drawing 
* CDT Corel Draw Template 
* CDX Corel Draw Compressed Drawing 
* CEL CIMFast Event Language
* CFB Comptons Multimedia
* CFG Ficheiro de configuración/preferencias dalgún programa
* CGI Common Gateway Interface
* CGM Computer Graphics Metafile 
* CH ficheiro de configuración para OS/2
* CHK Formato co que se gardan framentos doutros ficheiros que recuperou a utilidade ScanDisk do Windows ou ben o seu desfragmentador de disco
* CHP Ventura Publisher "chapter" (*capítulo*)
* CIL Paquete de descarga de clips multimedia para Office
* CIN OS/2 change control file that tracks changes to an INI file 
* CK1 Ficheiro de datos para iD/Apogee Commander Keen (sucesivos ficheiros terían extensións como .CK2, CK3 etc.)
* CLASS Java class 
* CLP Windows Clipboard
* CLS Visual Basic Class Module 
* CMD Ficheiro de comandos para Windows NT (similar ao ficheiro .BAT de MS-DOS); ficheiro de comandos para DOS CP/MM ficheiro de programa para dBase-II.
* CMF Corel Metafile 
* CMP JPEG Bitmap 
* CMV Animación do Corel Move
* CMX Formato de imaxe do Corel Presentation Exchange
* CNF Formato para expresar ficheiro de configuración en diferentes programas e contornos
* CNM Configuracións do Windows
* CNQ Compuworks Design Shop
* CNT "Content"
* COB Obxecto trueSpace2
* COD Compilador para *C*
* COM Ficheiro de comandos
* CPD Fax Cover document 
* CPE Fax Cover document 
* CPI "Code Page Information" (en MS-DOS)
* CPL Extensión do Panel de Control
* CPL Corel colour palette 
* CPP Código en C++
* CPR Corel Presents Presentation 
* CPT Corel Photo-Paint image 
* CPX Corel Presentation Exchange Compressed
* CRD Cardfile file 
* CRP Corel Presents Run-Time Presentation 
* CRT Certificate file 
* CSC Corel Script 
* CSP PC Emcee On-Screen image
* CSS Cascading Style Sheets
* CSV "Comma-separated values" 
* CT Scitex CT Bitmap 
* CTL Formato usado en xeral para introducir información de control 
* CUE Microsoft Cue Cards data 
* CUR Windows Cursor 
* CUT Dr Halo bitmap 
* CV Corel Versions archive 
* CV Pntalla de información para Microsoft CodeView
* CWK Ficheiro de datos Claris Works 
* CWS Sobreplanta Claris Works
* CXX Ficheiro de recursos de código C++

## D 
* DAT Datos
* DAT Datos de WordPerfect
* DBF Aston-Tate dBASE (base de datos)
* DBX Imaxe DataBeam
* DCR Ficheiro de Shockwave
* DCS Desktop Color Separation
* DCX Imaxe Fax (baseada no formato PCX)
* DDF BTRIEVE (base de datos)
* DEF Ficheiro de datos para SmartWare II
* DEF Definicións da linguaxe de programación C++
* DER Ficheiro de certificacións
* DIB "Device-Independent Bitmap" (recurso independente de mapa de bits)
* DIC Dicionario
* DIF Data Interchange Format
* DIR Macromedia Director
* DIZ Descrición
* DLG Script de diálogo para a linguaxe de programación C++
* DLL Dynamic-Link Library 
* DMF X-Trakker music module (MOD)
* DOC Documento para FrameMaker ou FrameBuilder, WordStar, Corel WordPerfect ou Microsoft Word
* DOT Sobreplanta para documentos de Microsoft Word
* DPP DrawPlus Drawing
* DPR Borland Delphi
* DRV Driver 
* DRW Micrografx Designer/Draw 
* DSM Módulo musical para Dynamic Studio (MOD)
* DSP Proxecto para Microsoft Developer Studio
* DSQ Corel QUERY
* DSW "Microsoft Developer Studio Workspace" (ambiente de traballo para Microsoft Developer Studio)
* DWG AutoCAD drawing eXchange
* DWT Sobreplanta para o AutCAD
* DXF Formato de intercambio para AutoDesk Drawing

## E 
* EMF "Enhanced Windows Metafile"
* EMZ "Windows Compressed Enhanced Metafile"
* ENC "Encore file"
* EPS Ficheiro de imaxe postcript encasulada
* ER1 Ficheiro de ERWin
* ERX Ficheiro de ERWin
* EVY Documennto de Envoy
* EWL Documento da Microsoft Encarta
* EXE Ficheiro executábel

## F 
* F FORTRAN file 
* F77 FORTRAN file 
* F90 FORTRAN file 
* FAR Farandole Composer
* FAV Barra de navegación do Microsoft Outlook
* FAX Formato de imaxe Fax
* FH3 Aldus Freehand 3
* FIF Imaxe fractal 
* FITS Imaxe de cámara CCD
* FLA Documento de Flash 
* FLC Animación para AutoDesk FLIC
* FLI Animación para AutoDesk FLIC
* FLT Filtor (*filter*)
* FLV Achivo de Video de Flash (FLashVideo)
* FON fonte bitmap
* FOR FORTRAN
* FOT Font-related
* FP FileMaker Pro
* FPX FlashPix
* FRM Form(ulario)
* FRM Formulario para Visual Basic
* FRM WordPerfect Merge
* FRX Formulario para Visual Basic

## G 
* GAL Galería fotográfica de Corel 
* GED Graphic Environment Document (imaxe) 
* GEM GEM metafile 
* GEN Ventura-Generated text file 
* GFC Patton&Patton Flowcharting 4 flowchart (imaxe)
* GFI Genigraphics Graphics Link
* GFX Genigraphics Graphics Link
* GID Ficheiro de indexación global para Windows 95
* GIF CompuServe bitmap (formato gráfico comprimido)
* GIM Genigraphics Graphics
* GIX Genigraphics Graphics
* GNA Genigraphics Graphics
* GNX Genigraphics Graphics
* GRA Microsoft Graph 
* GRD Grid file 
* GRP Program Manager Group 
* GTK Módulo musical (antigo) para Graoumftracker
* GT2 Módulo musical (novo) para Graoumftracker 
* GWX Genigraphics Graphics Link
* GWZ Genigraphics Graphics Link
* GZ Unix Gzip (ficheiro comprimido)

## H 
* H Cabeceira de programa na linguaxe de programación C
* HED HighEdit
* HEX Macintosh BinHex 2.0
* HGL HP Graphics Language
* HLP Ficheiro de axuda (*help*)
* HOG Lucas Arts Dark Forces WAD file 
* HPJ Visual Basic Help Project 
* HPP C++ program header 
* HQX Macintosh BinHex 4.0 file 
* HST Historial
* HT HyperTerminal 
* HTM Hypertext Markup Language
* HTML Hypertext Markup Language
* HTX Sobreplanta estendida para HTML

## I 
* ICA Citrix file 
* ICB Targa bitmap 
* ICM Image Color Matching profile file 
* ICO Windows Icon 
* IDD MIDI Instrument Definition 
* IDQ Internet Data Query file 
* IFF Amiga ILBM 
* IGF Inset Systems metafile 
* IIF QuickBooks for Windows interchange file 
* IMA WinImage file 
* IMG GEM image 
* INC Assembler language or Active Server include file 
* INF Information file 
* INI Initialization file 
* INP Oracle source code for form, versión 3.0 and earlier 
* INS InstallShield install script 
* INS X-Internet sign-up file 
* ISO Lists the files on a CD-ROM; based on the ISO 9660 CD-ROM file system standard 
* ISP X-Internet sign-up file 
* ISU InstallShield uninstall script 
* IT Impulse Tracker music module (MOD) file 
* IW Idlewild screensaver

## J 
* JAR Java ARchive file (ficheiro comprimido) 
* JAVA Recursos de código para linguaxe Java 
* JBF Paint Shop Pro
* JFF formato de imaxe (mapa de bits)
* JIF formato de imaxe (mapa de bits)
* JPEG imaxe comprimida
* JPG imaxe comprimida
* JS Recursos de código para linguaxe Java 
* JTF mapa de bits

## K 
* KAR Arquivos para Karaoke
* KDC Kodak Photo-Enhancer 
* KFX KoFax Group 4

## L 
* LBM Deluxe Paint Bitmap 
* LDB Microsoft Access Lock
* LEG Documento (leg)al
* LHA Extensión alternativa para os ficheiros LZH
* LIB Library 
* LOG Ficheiro lóxico (log)
* LRC Extensão para letras de música en sincronía co ficheiro MP3 da mesma música (usado en karaoke e reprodutores MP3)
* LRC Intel Video Phone
* LST Ficheiro de listas
* LWO Lightwave Object
* LWP Lotus Wordpro 96/97
* LZH Ficheiro comprimido LH ARC

## M 
* M3D Animación para Corel Motion 3D
* MAC MacPaint (imaxe)
* MAD Microsoft Access
* MAF Microsoft Access Form 
* MAK Proxecto para Visual Basic ou proxecto para MS Visual C++
* MAM Microsoft Access Macro 
* MAP Map(a)
* MAQ Microsoft Access Query 
* MAR Microsoft Access Report (informe)
* MAS Lotus Freelance Graphics Smartmaster
* MAT Microsoft Access Table
* MAX Paperport file 
* MAX Extensión nativa do 3D Studio Max.
* MAZ Hover maze data 
* MCC Chamadas do Dialer10
* MCS MathCAD (imaxe)
* MCW Microsoft Word para Macintosh
* MDA Microsoft Access add-in 
* MDB Base de datos para Microsoft Access
* MDE Microsoft Access MDE
* MDL Digital Tracker music module (MOD)
* MDN Microsoft Access (sobreplanta)
* MDW Microsoft Access Workgroup 
* MDZ Microsoft Access (sobreplanta)
* MER Formato de intercambio para diferentes programas(como Filemaker ou Excel) 
* MET Presentation Manager *(met)afile*
* MHTML (.mht, .mhtml) - Ficheiro HTML que almacena todos os datos dunha páxina web (texto, imaxes e multimedia) nun só documento
* MI Misceláneo (*miscellaneous*)
* MIC Microsoft Image Composer
* MID Formato musical MIDI (equivalente vectorial para os ficheiros de son, posto que só representa magnitudes musicais)
* MKA Son comprimido no formato Matroska
* MKV Vídeo comprimido no formato Matroska
* MMF Microsoft Mail File 
* MMM Microsoft Multimedia Movie
* MMM fonte PostScript Type 1 (Multiple Master)
* MOD Módulo ou modificador (para diferentes aplicacións)
* MOV Película (*movie*) para QuickTime
* MPEG ou MPG Moving Picture Experts Group
* MPP Microsoft Project
* MPP CAD drawing file format 
* MP3 MPEG Audio Layer 3 (AC3)
* MSG Microsoft Mail
* MSN Microsoft Network
* MSP Microsoft Paint (mapa de bits)
* MTM MultiTracker Music Module
* MUS Music 
* MVB Microsoft Multimedia Viewer
* MWP Lotus Wordpro 97 Smartmaster

## N 
* NAP NAP Metafile 
* NCB Microsoft Developer Studio
* NSF Base de datos Lotus Notes
* NST Módulo musical para Noise Tracker
* NTF Sobreplanta para bases de datos Lotus Notes
* NRG Imaxe do programa de gravación Nero

## O 
* OBD Sobreplanta para Microsoft Office Binder
* OBD Microsoft Office Binder 
* OBJ Obxecto (*object*)
* OBZ Microsoft Office Binder Wizard 
* OCX Microsoft Object Linking and Embedding Custom Control
* ODF OpenDocument Format
* OFN Microsoft Office FileNew
* OFT Microsoft Outlook (sobreplanta)
* OGG Formato de compresión de son, aberto e libre
* OKT Oktalyzer
* OLB OLE Object Library 
* OLE Obxecto OLE
* OPT Microsoft Developer Studio
* ORG Lotus Organiser
* OR2 Lotus Organiser 2
* OR3 Lotus Organiser 97
* OTF fonte OpenType

## P 
* P10 Tektronix Plot 10
* PAB Caderno de direccións de Microsoft (*Personal Address Book *)
* PAL PAleta de cores
* PAT Modelo (*pattern*) para Corel Draw
* PBK Microsoft Phonebook 
* PBM Mapa de bits portátil (*Portable Bitmap *)
* PCD Kodak Photo-CD
* PCS PICS animation 
* PCT Macintosh PICT drawing 
* PCX ZSoft PC Paintbrush (formato de imaxe)
* PDF Adobe Acrobat Portable Document Format
* PDF Netware Printer Definition File 
* PDF Package Definition File from Microsoft Systems Management Server 
* PDQ Patton&Patton Flowcharting PDQ Lite file 
* PFA fonte PostScript Tipo 1 (ASCII) 
* PFB fonte PostScript Tipo 1 (binario) 
* PFC PF Component 
* PFM fonte PostScript Tipo 1 (Printer Font Metrics)
* PGL HP Plotter drawing 
* PGM Portable Graymap (bitmap) 
* PIC PC Paint bitmap 
* PIC Lotus picture 
* PIC Macintosh PICT drawing 
* PIF Program Information File
* PIX Inset Systems bitmap
* PKG Microsoft Developer Studio (similar a DLL)
* PL Ficheiro para a linguaxe de programación Perl
* PLT HPGL Plotter
* PLT AutoCAD Plot
* PM5 Pagemaker 5.0
* PM6 Pagemaker 6.0
* P65 Pagemaker 6.5
* PNG Portable Network Graphics bitmap (imaxe vectorial)
* PNG Catálogo para Paint Shop Pro Browser
* PNT MacPaint graphic
* POT Microsoft PowerPoint Template 
* PP4 Picture Publisher 4
* PPA Microsoft PowerPoint Add-in 
* PPM Portable Pixelmap bitmap
* PPP PagePlus Publication 
* PPS Microsoft PowerPoint
* PPT Microsoft PowerPoint
* PRE Lotus Freelance presentation 
* PRF Windows system file 
* PRN Print Table
* PRS Presentación de Harvard Graphics para Windows
* PRZ Lotus Freelance Graphics 97
* PS Postscript Interpreted drawing 
* PSD Adobe Photoshop bitmap 
* PST Microsoft Outlook Personal Folder
* PTM Módulo musical de Polytracker
* PUB Ventura Publisher
* PUB Microsoft Publisher
* PWD Microsoft Pocket Word
* PWZ Microsoft PowerPoint Wizard 
* PXL Microsoft Pocket Excel
* PY Python
* PYW Python File Without Console

## Q 
* QAD PF QuickArt Document 
* QBW QuickBooks para Windows
* QDT Quick Books 
* QLB Quick Library 
* QRY Microsoft Query 
* QT QuickTime Movie 
* QTM QuickTime Movie 
* QXD Quark XPress

## R 
* R Pegasus Mail resource file 
* RA Real Audio sound 
* RAM Real Audio sound 
* RAS Sun Raster Images bitmap 
* RAW Raw File Format (bitmap) 
* RC Microsoft Visual C++ Resource Script 
* REC Recorder macro 
* REG Registration file 
* RES Microsoft Visual C++ Resource 
* RFT RFT-DCA 
* RLE Run-Length Encoded bitmap 
* RM Real Audio video
* RMI MIDI music 
* ROV Rescue Rover
* RPT Microsoft Visual Basic Crystal Reports
* RTF Formato de Texto Enriquecido (Rich Text Format)
* RTM Módulo musical Real Tracker

## S 
* SAM Ami Professional
* SAV Saved game
* SCC Microsoft Source Safe
* SCD Matrix/Imapro SCODL
* SCD Microsoft Schedule+ 7 
* SCH Microsoft Schedule+ 1 
* SCN escena (*scene*) para trueSpace2 
* SCP Dial-Up Networking Script 
* SCR Windows screensaver 
* SCR Fax image 
* SCT Scitex CT bitmap 
* SC2 Microsoft Schedule+ 7 
* SDL SmartDraw library 
* SDR SmartDraw drawing 
* SDT SmartDraw template 
* SEA Self-expanding archive
* SEP Tagged Image File Format (TIFF) bitmap 
* SHB Corel Show
* SHB Document shortcut
* SHG Hotspot bitmap 
* SHS Shell scrap file 
* SHW Corel Show presentation 
* SKP extensión de ficheiro 3D do SketchUp.
* SIT Stuffit archive of Mac files 
* SLK Symbolic Link (SYLK) spreadsheet 
* SND NeXT sound 
* SND Mac Sound Resource 
* SPP PhotoPlus Pictures
* SQC Structured Query Language (SQR) common code file 
* SQR Structured Query Language (SQR) program file 
* STM Scream Tracker music module (MOD) file 
* STY Ventura Publisher style sheet 
* SVG Scalable Vector Graphics
* SVX Amiga 8SVX sound 
* SWF Shockwave Flash Object
* SYS System file 
* S3M Scream Tracker 3 music module (MOD) file

## T 
* TAR Tape Archive 
* TAZ Unix Gzip/Tape Archive 
* TEX Texture file 
* TGA Targa bitmap 
* TGZ Unix Gzip/Tape Archive 
* THEME Windows 95 Desktop Theme 
* THN Graphics Workshop for Windows thumbnail 
* TIF ou TIFF Tag Image File Format (TIFF) bitmap 
* TIG Tiger file, used by US government to distribute maps 
* TLB OLE Type Library 
* TMP Windows temporary file 
* TRM Terminal file 
* TRN MKS Source Integrity project usage log 
* TTF fonte TrueType
* TWF TabWorks file 
* TWW Tagwrite Template 
* TX8 MS-DOS Text 
* TXT Text 
* T2T Sonata CAD modelling software file

## U 
* UDF Windows NT Uniqueness Database File 
* ULT Ultratracker music module (MOD) file 
* URL Internet shortcut 
* USE MKS Source Integrity file

## V 
* VBP Visual Basic Project 
* VBW Microsoft Visual Basic workspace 
* VBX Visual Basic custom control 
* VCF Vevi Configuration File; defines objects for use with Sense8's WorldToolKit 
* VDA Targa bitmap 
* VI Virtual Instrument file from National Instruments LABView product 
* VLB Corel Ventura Library 
* VOC Creative Labs Sound Blaster sound 
* VP Ventura Publisher publication 
* VSD Visio drawing (flow chart or schematic) 
* VST Targa bitmap 
* VSW Visio Workspace file 
* VXD Microsoft Windows virtual device driver

## W 
* WAD Large file for Doom game containing video, player level, and other information 
* WAV Windows Waveform sound 
* WB1 QuattroPro for Windows spreadsheet 
* WB2 QuattroPro for Windows spreadsheet 
* WBK Microsoft Word Backup 
* WBL Argo WebLoad II upload file 
* WCM WordPerfect Macro 
* WDB Microsoft Works database 
* WEB CorelXara Web document 
* WGP Wild Board Games data file 
* WID Ventura width table 
* WIL WinImage file 
* WIZ Microsoft Word Wizard 
* WK1 Lotus 123 versions 1 & 2 spreadsheet 
* WK3 Lotus 123 version 3 spreadsheet 
* WK4 Lotus 123 version 4 spreadsheet 
* WKS Lotus 123 Worksheet spreadsheet 
* WKS Microsoft Works document 
* WLF Argo WebLoad I upload file 
* WLL Microsoft Word Add-In 
* WMF Windows Metafile 
* WOW Grave Composer music module (MOD) file 
* WP WordPerfect document 
* WPW Novel PerfectWorks document 
* WP4 WordPerfect 4 document 
* WP5 WordPerfect 5 document 
* WP6 WordPerfect 6 document 
* WPD WordPerfect Demo 
* WPD WordPerfect Document 
* WPG WordPerfect Graphic 
* WPS Microsoft Works document 
* WPT WordPerfect Template
* WQ1 QuattroPro/DOS spreadsheet 
* WQ2 QuattroPro/DOS version 5 spreadsheet 
* WRI Write document 
* WRL Virtual Reality model 
* WS1 WordStar for Windows 1 document 
* WS2 WordStar for Windows 2 document 
* WS3 WordStar for Windows 3 document 
* WS4 WordStar for Windows 4 document 
* WS5 WordStar for Windows 5 document 
* WS6 WordStar for Windows 6 document 
* WS7 WordStar for Windows 7 document 
* WSD WordStar 2000 document 
* WVL Wavelet Compressed Bitmap

## X 
* XAR Corel Xara drawing 
* XLA Microsoft Excel add-in 
* XLB Microsoft Excel toolbar 
* XLC Microsoft Excel chart 
* XLD Microsoft Excel dialogue 
* XLK Microsoft Excel backup 
* XLM Microsoft Excel macro 
* XLS Microsoft Excel worksheet 
* XLT Microsoft Excel template 
* XLV Microsoft Excel VBA module 
* XLW Microsoft Excel workbook / workspace 
* XM FastTracker 2, Digital Tracker music module (MOD) file 
* XR1 Epic MegaGames Xargon data file 
* XTP XTree data file 
* XY3 XYWrite III document 
* XY4 XYWrite IV document 
* XYP XYWrite III Plus document 
* XYW XYWrite for Windows 4.0 document

## Y 
* YAL Arts & Letters clipart library 
* YBK Microsoft Encarta Yearbook

## Z 
* Z Unix Gzip 
* ZIP Zip file 
* ZOO An early compressed file format