List of filename extensions (A–E)

This alphabetical list of filename extensions contains extensions of notable file formats used by multiple notable applications or services.

Contents

• !$@
• 0-9
• A
• B
• C
• D
• E
• F
• G
• H
• I
• J
• K
• L
• M
• N
• O
• P
• Q
• R
• S
• T
• U
• V
• W
• X
• Y
• Z

• See also
• References

A

Ext.	Description	Used by
A	Archive file	ar (Unix)
AAC	Advanced Audio Coding file	iOS, Nintendo DSi, Nintendo 3DS, YouTube Music
ACCDB[1]	Microsoft Access Database	Microsoft Access Database (Open XML)
ACCFT[2]	Microsoft Access Data Type Template	Microsoft Access
ACO	Adobe color palette format (.aco)[3]	Adobe Photoshop[4]
ADT	Abrechnungsdatentransfer, an xDT application	Healthcare providers in Germany
ADX	Document	Archetype Designer
ADZ	Amiga Disk Zipped (See Amiga Disk File)	GZip
AGDA	Agda (programming language) source file	Agda typechecker/compiler
AGR	ArcView ASCII grid
AHK	AutoHotkey script file	AutoHotkey
AI[5]	Adobe Illustrator Artwork	Adobe Illustrator
AIFF[6]	Audio Interchange File Format	professional audio processing applications and on Macintosh[7]
AIFC[6]	Compressed Audio Interchange File Format
AIO	APL programming language file transfer format file
AMF[8][9]	Additive Manufacturing File Format	Computer Aided Design Software
AMG	System image file	ACTOR
AML[10]	AutomationML	AutomationML Group
AMLX[10]	Compressed and packed AutomationML file	AutomationML Group
AMPL	AMPL source code file	AMPL
AMR	Adaptive Multi-Rate audio
AMV	Actions Media Video
ANI[11]	Animation cursors for Win	Win95 - WinNT
ANN	Annotations of old Windows Help file	Windows 3.0 - XP
APE	Monkey's Audio (Lossless)	audio media players
APK	Android application package	Android
APK	Alpine Linux Package	Alpine Linux and derivatives
ARC[12]	ARC (file format)
ART[13]	Gerber format	Cadence Allegro, EAGLE
ASAX[14]	ASP.NET global application file
ASCX[14]	ASP.NET User Control
ASF[15]	Advanced Streaming Format (Compressed Windows audio/video)	Microsoft Corporation
ASHX[14]	ASP.NET handler file
ASM	Assembler language source	TASM, MASM, NASM, FASM
ASPX	Active server page extended file	Microsoft Corporation
ASX[16]	Advanced Stream Redirector file, redirects to an ASF file (see ASF)	Microsoft Corporation
ATG[17]	Coco/R LL(1) formal grammar	Coco/R
AT3[18]	Atrac 3 Sound/music file	All Sony devices and programs with the Atrac 3+ specification
AU	audio file[19]
AVI[20][21]	Audio Video Interleave	Video for Windows
AVIF	AV1 Image File Format
AWK	AWK script/program	awk, GNU Awk, mawk, nawk, MKS AWK, Awka (compiler)
AX	DirectShow Filter	Microsoft Corporation (Video Players)
AXF[22]	lightweight geodatabase	ESRI ArcPad

B

Ext.	Description	Used by
B	BASIC language source
B	bc arbitrary precision calculator language file	Unix bc tool
B64	base64 binary-to-text encoding[23]
BAK	backup	various
BAR	Broker Archive. Compressed file containing number of other files for deployment.[24]	IBM App Connect
BAS	BASIC language source	QuickBASIC - GW-BASIC - FreeBASIC - others
BAT	Batch file	MS-DOS, RT-11, DOS-based command processors
BDF	Glyph Bitmap Distribution Format, a format used to store bitmap fonts.	Adobe
BDT	Behandlungsdatentransfer, an xDT application	Healthcare providers in Germany
BEAM	Executable bytecode file in fat binary format	BEAM (Erlang virtual machine)[25]
BIB	Bibliography database	BibTex
BIN	binary file	Every OS
BLEND	Blender project file	Blender
BM3	UIQ3 Phone backup
BMP[26]	OS/2 or Win graphics format (BitMap Picture)	QPeg - CorelDraw - PC Paintbrush - many
BPS	WPS backup file[27]	Microsoft Word, Microsoft Works
BSON	JSON-like binary serialization[28]	MongoDB
BSP	Binary space partitioning tree file	Quake-based game engines
BYU	3D geometry format[29]	CAD systems
BZ2[30]	Archive	bzip2

C

Ext.	Description	Used by
C--	C-- language source	Sphinx C--
C	C language source Note that on case-sensitive platforms like Unix and with the gcc compiler the uppercase .C extension indicates a C++ source file.[31]	Watcom C/C++, Borland C/C++, gcc and other C compilers
C	Unix file archive	COMPACT
C++	C++ language source
CPP	C++ language source
Config	Configuration file
C32	COMBOOT Executable (32-bit)	SYSLINUX
CAB[32]	Cabinet archive	Windows 95 and later, many file archivers
CBL[33]	COBOL language source
CBT	COMBOOT Executable (incompatible with DOS COM files)	SYSLINUX
CC	C++ language source
CD	ASP.NET class diagram file[14]
CDF[34]	Common Data Format
CDF[35]	Computable Document Format	Mathematica
CDP[36]	Trainz Railroad Simulator Content Dispatcher Pack	Trainz Railroad Simulator
CDR[37]	Vector graphics format (drawinF	CorelDraw
CDXML	MIME type: chemical/x-cdxmlXML version of the ChemDraw Exchange format, CDX.[38]
CER[39]	Security certificate	Microsoft Windows
CGM[40][41]	Computer Graphics Metafile vector graphics	A&L - HG - many
CHM[42]	Compiled Help File	Microsoft Windows, Help Explorer Viewer
CHO[43]	ChordPro lead sheet (lyrics and chords)	ChordPro and similar tools
CIA	Decrypted Nintendo 3DS ROM cartridge	Nintendo 3DS
CIF[44][45]	Crystallographic Information File	RasMol, Jmol
CLASS[46]	Java class file	Java
CLS	ooRexx class file	ooRexx
CMD	Command Prompt batch file	Microsoft Windows NT based operating systems
CMD[47]	executable programs	CP/M-86 operating system
CML	Chemical Markup Language, for interchange of chemical information.[48]
CMOD[49]	Celestia Model	Celestia
CN1[50]	CNR IDL	MITRE
CNOFF	3D object file format with normals (.noff, .cnoff)[51] NOFF is an acronym derived from Object File Format. Occasionally called CNOFF if color information is present.[52]
COB[53]	COBOL language source	GnuCOBOL
COE[54]	Coefficient file	Xilinx ISE
COFF	3D object file format (.off, .coff)[55] OFF is an acronym for Object File Format. Used for storing and exchanging 3D models. Occasionally called COFF if color information is present.[56]
COL	DIMACS graph data format.[57]
COM	DOS program	DOS-
COMPILE[14]	ASP.NET precompiled stub file
CPC[58]	Compressed image	Cartesian Perceptual Compression
CPIO	cpio archive file	cpio
CPL[59]	Control panel file	Windows 3.x
CPY[53]	COBOL source copybook file
CR2[60]	Raw image format	Canon digital cameras
CR3[61]	Raw image format	Canon R series cameras
CRAI[62]	CRAM index
CRAFT	Holds Spacecraft Assembly information	Kerbal Space Program
CRT[39]	Security certificate	Microsoft Windows
CS[63]	C# language source
CSPROJ[64][65]	C# project file	Microsoft Visual Studio
CSS[66]	Cascading style sheet
CSO[67]	Compiled Shader Object, extension of compiled HLSL	High-Level Shading Language
CSV[68]	Comma Separated Values text file format (ASCII)
CUB	Used by electronic structure programs to store orbital or density values on a three-dimensional grid.[69]
CUBE	same as .cub
CUR	Non-animated cursor (extended from ICO)	Windows

D

Ext.	Description	Used by
D	D Programming Language source file	DMD
D	Directory containing configuration files (informal standard)	Unix
DAA	Direct Access Archive
DAE	COLLADA file
DAF	Data file	Digital Anchor
DART	Dart (programming language) source file
DAT	AMPL data file	AMPL
DAT	LDraw (Sub)Part File, 3D Model	LDraw
DAT	Data	RSNetWorx Project
DAT	Data file in special format or ASCII
DAT	Database file	Clarion (programming language)
DAT	Norton Utilities disc image data. It saves Boot sector, part of FAT and root directory in image.DAT on same drive.	Norton Utilities
DAT	Optical disc image (can be ISO9660, but not restricted to)	cdrdao, burnatonce
DAT	Video CD MPEG stream
DAT	Windows registry hive (REG.DAT Windows 3.11; USER.DAT and SYSTEM.DAT Windows 95, 98, and ME; NTUSER.DAT Windows NT/2000/XP/7)	Microsoft Windows
DATS	Dynamic source	ATS
DB	Database file	DB Browser for SQLite
DBA	DarkBasic source code
DBC	Database Connection configuration file	AbInitio
DBF	Native format of the dBASE database management application.[70]
DBG	Debugger script	DOS debug - Watcom debugger
DBG	Symbolic debugging information	Microsoft C/C++
DEB	deb software package	Debian Linux and derivatives
DEM	digital elevation model (DEM) including GTOPO30 and USGSDEM. GTOPO30 is a distribution format for a global digital elevation model (DEM) with 30-arc-second grid spacing.[71] USGSDEM is the standard format for the distribution of terrain elevation data for the United States.[72]
DGN	CAD Drawing	Bentley Systems, MicroStation and Intergraph's Interactive Graphics Design System (IGDS) CAD programs
DICOM	Digital Imaging and Communications in Medicine (DICOM) bitmap	DICOM Software (XnView)
DIF	Data Interchange Format	Visicalc
DIF	Output from [diff] command - script for Patch command
DIRED	Directory listing (ls format)	Dired
DIVX	DivX media format
DMG	Apple Disk Image	macOS (Disk Utility)
DMP	memory dump file (e.g. screen or memory)
DN	Dimension model format	Adobe Dimension[73]
DNG[74]	Digital Negative, a-publicly available archival format for the raw files generated by digital cameras	At least 30 camera models from at least 10 manufacturers, and at least 200 software products
DOC[75][76][77]	A Document, or an ASCII text file with text formatting codes in with the text; used by many word processors	Microsoft Word and others
DOCM	Microsoft Word Macro-Enabled Document	Microsoft Word
DOCX[78]	Microsoft Word Document	Microsoft Word
DOT[78]	Microsoft Word document template	Microsoft Word
DOTX[78]	Office Open XML Text document template	Microsoft Word
DPX[79][80]	Digital Picture Exchange
DRC	Dirac format video
DSC[81]	Celestia Deep Space Catalog file	Celestia
DTA	Stata database transport format.[82]	Stata
DTD[83]	Document Type Definition
DVC[84]	Data version control yaml pointer into blob storage
DWF	Autodesk Design Web Format	Design Review
DWG[85]	Drawing	AutoCAD, IntelliCAD, PowerCAD, Drafix, DraftSight etc.
DX	same as JDX and JCM.
DXF[86]	Drawing Interchange File Format vector graphics	AutoCAD, IntelliCAD, PowerCAD, etc.

E

Ext.	Description	Used by
E	E language source code	E
E##	EnCase Evidence File chunk	EnCase Forensic Analysis Suite entity
E00	ArcInfo interchange file	GIS software
E2D	2-dimensional vector graphics file	Editor included in JFire
e57	A file format developed by ASTM International for storing point clouds and images	Most software that enables viewing and/or editing of 3D point clouds
EBD	versions of DOS system files (AUTOEXEC.BAT, COMMAND.COM, CONFIG.SYS, WINBOOT.SYS, etc.) for an emergency boot disk	Windows 98, ME
EC	Source code	eC
ECC	Error-checking file	dvdisaster
EDE	Ensoniq EPS disk image	AWAVE
EDF	European data format	Medical timeseries storage files
EFI	Extensible Firmware Interface
EIS	EIS Spectrum Analyser Project	EIS Spectrum Analyser Archived 2010-03-29 at the Wayback Machine
EL	Emacs Lisp source code file	Emacs
ELC	Byte-compiled Emacs Lisp code	Emacs
ELF	Executable and Linkable File EurekaLog File (contains details of an exception)	Unix EurekaLog (https://www.eurekalog.com/)
EMAIL	Outlook Express Email Message	Windows Live Mail, Outlook Express, Microsoft Notepad
EMAKER	E language source code (maker)	E
EMF	Microsoft Enhanced Metafile
EML	Email conforming to RFC 5322;[87] Stationery Template	Email clients;Outlook Express
EMZ	Microsoft Enhanced Metafile compressed with ZIP	Microsoft Office suite
EOT	Embedded OpenType
EP	GUI wireframe/prototype project	Prikhi Pencil, Evolus Pencil
EPA	Award BIOS splash screen	Award BIOS, XnView
EPS	Encapsulated PostScript	CorelDraw - PhotoStyler - PMView - Adobe Illustrator - Ventua Publisher
EPUB	Electronic Publication (e-Reader format)	Okular (Linux) - Apple Books - Sony Reader - Adobe Digital Editions - Calibre (LMW)
EU4	Europa Universalis 4 save game file	Europa Universalis 4
ERL	Erlang source code file
ES6	ECMAScript 6 file
ESCPCB	Data file of "esCAD pcb", PCB Pattern Layout Design Software	esCAD pcb provided by Electro-System
ESCSCH	Data file of "esCAD sch", Drawing Schematics Diagram Software	esCAD sch provided by Electro-System
ESD	Windows Imaging Format	ImageX, DISM, 7-Zip, wimlib
ETL	event trace log file	Microsoft[88][89]
EVT	Windows Event log file	Microsoft Windows NT 4.0 - XP; Microsoft Event Viewer
EVTX	Windows Event log file XML structured	Microsoft Windows Vista, 7, 8; Microsoft Event Viewer
EX	Elixir source code file	Elixir programming language running on BEAM (Erlang virtual machine)[90]
EXE	Directly executable program	DOS, OpenVMS, Microsoft Windows, Symbian or OS/2
EXP	Drawing File format	Drawing Express
EXP	Melco Embroidery Format	Embroidermodder
EXR	OpenEXR raster image format (.exr).[55] Used in digital image manipulation for theatrical film production. EXR is an acronym for Extended Dynamic Range. Stores 16 bit per pixel IEEE HALF-precision floating-point color channels. Can optionally store 32-bit IEEE floating-point "Z" channel depth-buffer components, surface normal directions, or motion vectors.[91]
EXS	Elixir script file	Interactive Elixir (IEx) shell[92]

See also

• List of filename extensions
• List of file formats

References

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2. "Save and reuse database design elements". Retrieved 29 October 2015.
3. "Listing of All Formats".
4. "ACO (.aco)". Wolfram Language & System Documentation Center.
5. "What is a vector file?". adobe.com. Retrieved 2020-09-12.
6. Tom Erbe (1999). "AIFF-C Compression Types and Names". Archived from the original on 2006-06-20. Retrieved 2010-03-21.
7. "AIFF (.aif, .aiff, .aifc)".
8. Specification for Data Exchange Format for Additive Manufacturing
9. Specification of AMF on ISO web page
10. "AutomationML". AutomationML e. V. Retrieved 2020-09-13.
11. "About animated cursors". gdgsoft.com. Retrieved 2020-09-14.
12. Burner, Mike; Kale, Brewster (1996-09-15). "Arc File Format". Retrieved 2020-09-13.
13. "Gerber Format". ucamco.com. 2020-04-09. Retrieved 2020-09-13.
14. ASP.NET Web Project File Types
15. "Overview of the ASF format". microsoft.com. 2018-05-31. Retrieved 2020-09-12.
16. "ASX Element". microsoft.com. 2018-05-31. Retrieved 2020-09-14.
17. "Coco/R own DSL grammar". github.com.
18. "ATRAC Developer's Interview". sony.net. Retrieved 2020-09-12.
19. "AU (.au)".
20. "AVI File Format with OpenDML Extensions, Version 1.02". www.loc.gov. 2016-03-09. Retrieved 2019-09-01.
21. stevewhims. "AVI RIFF File Reference - Windows applications". docs.microsoft.com. Retrieved 2019-09-01.
22. "The ArcPad Team Blog: What is an ArcPad AXF?".
23. "Base64 (.b64)".
24. "Deploying integration solutions". ibm.com. Retrieved 2021-05-18.
25. "The Erlang Runtime System". happi.github.io. Retrieved 2018-05-07.
26. "Bitmap Storage". microsoft.com. 2018-05-31. Retrieved 2020-09-12.
27. "BPS File Extension - What is a .bps file and how do I open it?". fileinfo.com. Retrieved 2018-10-12.
28. "BSON (.bson)".
29. "BYU (.byu)".
30. "BZIP2 Format Specification" (PDF). GitHub. 27 February 2022.
31. "Overall Options - Using the GNU Compiler Collection (GCC)". gcc.gnu.org. Retrieved 2020-06-27.
32. "Cabinet Files". microsoft.com. 2018-05-31. Retrieved 2020-09-13.
33. Coughlan, Michael (16 March 2014). Beginning COBOL for Programmers. Apress. p. 400. ISBN 978-1430262534. Retrieved 13 August 2014.
34. "What is Common Data Format (CDF)?". Retrieved 2020-09-13.
35. "Computable Document Format". wolfram.com. Retrieved 2020-09-12.
36. "CDP File - What is it and how do I open it?". file.org. Retrieved 2022-10-28.
37. "Trying to Open a .CDR File?". Retrieved 2020-09-12.
38. "CDXML (.cdxml)".
39. "Certificate extensions explained". digicert.com. Retrieved 2020-09-12.
40. IANA Image Media Types
41. ISO/IEC 8632
42. "Create a Help Project". 2018-05-31. Retrieved 2020-09-12.
43. "Welcome to ChordPro!". Retrieved 2020-09-12.
44. Hall SR, Allen FH, Brown ID (1991). "The Crystallographic Information File (CIF): a new standard archive file for crystallography". Acta Crystallographica Section A. 47 (6): 655–685. doi:10.1107/S010876739101067X.
45. Brown ID, McMahon B (2002). "CIF: the computer language of crystallography". Acta Crystallographica Section B: Structural Science. 58 (Pt 3 Pt 1): 317–24. doi:10.1107/s0108768102003464. PMID 12037350.
46. "The class File Format". oracle.com. Retrieved 2020-09-12.
47. Elliott, John C. "CP/M-86 executables (.CMD)". Seasip.info. Archived from the original on 2016-11-14. Retrieved 2016-08-29.
48. "CML (.cml)".
49. "Celestia's CMOD model format". Retrieved 2020-09-12.
50. "MITRE's Combat Net Radio Initialization File". Retrieved 2020-11-30.
51. "Listing of All Formats".
52. "NOFF (.noff, .cnoff)".
53. Cutler, Gary; Coen, Vincent (July 2020). "10.1. Compiling Programs". GnuCOBOL Programmer's Guide (3.1 RC-1 ed.).
54. "COE File Syntax". xilinx.com. 2009.
55. "Listing of All Formats".
56. "OFF (.off, .coff)".
57. "DIMACS (.col, .col.b)".
58. "Technical Overview of Cartesian Perceptual Compression". 1999. Retrieved 2020-09-13.
59. "Description of Control Panel (.cpl) Files". microsoft.com. 2020-08-19. Retrieved 2020-09-12.
60. "Understanding What is stored in a Canon RAW .CR2 file, How and Why". Retrieved 2020-09-12.
61. "Quick look: Canon's new compressed Raw format". DPReview. Retrieved 2023-07-15.
62. Hsi-Yang Fritz, Markus; Leinonen, Rasko; Cochrane, Guy; Birney, Ewan (May 2011). "Efficient storage of high throughput DNA sequencing data using reference-based compression". Genome Research. 21 (5): 734–740. doi:10.1101/gr.114819.110. ISSN 1549-5469. PMC 3083090. PMID 21245279.
63. "Introduction to projects and solutions". docs.microsoft.com. 2020-11-17. Retrieved 2021-05-06.
64. "Additions to the csproj format for .NET Core". microsoft.com. 2019-04-28. Retrieved 2020-09-12.
65. "Understanding the project file". microsoft.com. 2012-05-04.
66. "Cascading Style Sheets home page". w3.org. Retrieved 2020-09-12.
67. "Compiling shaders home page". w3.org. Retrieved 2023-03-28.
68. Shafranovich, Y. (October 2005). Common Format and MIME Type for CSV Files. IETF. p. 1. doi:10.17487/RFC4180. RFC 4180.
69. "Cube (.cub, .cube)".
70. "DBF (.dbf)".
71. "GTOPO30".
72. "USGSDEM (.dem)".
73. Adobe Dimension User Guide
74. "Digital Negative (DNG)". Adobe Systems Incorporated. Retrieved 2018-07-30.
75. Microsoft Office Binary (doc, xls, ppt) File Formats, 2008-02-15, archived from the original on 2008-02-18
76. "Microsoft Office Word 97 - 2007 Binary File Format Specification (*.doc)" (PDF). Microsoft Corporation. 2008.
77. MS-DOC: Word (.doc) Binary File Format, 2019-11-19, retrieved 2020-02-25
78. "Word Extensions to the Office Open XML (.docx) File Format". 2020-08-18. Retrieved 2020-08-29.
79. ST 268-1:2014 - SMPTE Standard - File Format for Digital Moving-Picture Exchange (DPX). SMPTE. doi:10.5594/SMPTE.ST268-1.2014. ISBN 978-1-68303-083-6.
80. ST 268-2:2018 - SMPTE Standard - Digital Moving-Picture Exchange (DPX) – Format Extensions for High Dynamic Range and Wide Color Gamut. SMPTE. doi:10.5594/SMPTE.ST268-2.2018. ISBN 978-1-68303-161-1. S2CID 252588275.
81. "DSC Parameters recognized by Celestia v1.4.1 (and later)". Retrieved 2020-09-13.
82. "DTA (.dta)".
83. "Extensible Markup Language (XML) 1.0". w3.org (5 ed.). 2008-11-26. Retrieved 2020-09-13.
84. "Data Version Control".
85. "Open Design Specification for .dwg Files" (PDF). opendesign.com. Retrieved 2020-09-13.
86. "DXF Reference" (PDF). autodesk.com. February 2011. Retrieved 2020-09-13.
87. ".EML File Extension". Archived from the original on 2021-08-12. Retrieved 2022-01-10.
88. "Windows Event Trace Log Sink". Microsoft TechNet. Microsoft. 2005-06-20. Retrieved 2017-02-08. The Event Trace Sink provided with the Microsoft Enterprise Instrumentation Framework (EIF) produces event trace log (.etl) files [...].
89. Compare: Rea, Sara Morgan (2005). Building Intelligent .NET Applications: Agents, Data Mining, Rule-based Systems, and Speech Processing. Addison-Wesley Microsoft Technology Series. Addison Wesley. p. 41. ISBN 9780321246264. Retrieved 2017-02-08. Each call is logged to the Windows Event Trace Log and stored in a log file with an .etl (event log tracing) extension.
90. "Modules and functions". elixir-lang.github.com. Retrieved 2018-05-07.
91. "OpenEXR (.exr)".
92. "Erlang/Elixir Syntax: A Crash Course". elixir-lang.github.com. Retrieved 2018-05-07.

External links

• File Extension Resource
• The File Extensions Resource
• File information site
• File format finder
• List of file types
• File format search engine