List of filename extensions (F–L) explained

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

F

Ext.	Description	Used by
	Forth language source code file	Forth development systems
	Fortran language source code file (in fixed form)	Many Fortran compilers
	Fax	perfectfax
	Fortran language source code file (in free form)	Many Fortran compilers
	Fortran language source code file (in free form)	Fortran compilers
	Fortran language source code file (in free form)	Fortran compilers
	Fortran IV source code file	Fortran IV source code
^[1]	A container format for Flash Video that differs from the older FLV file format (see also SWF)	Adobe Flash
	Fortran language source code file (in fixed form)	Many Fortran compilers
	Fortran language source code file (in free form)	Many Fortran compilers
	Fortran language source code file (in free form)	Many Fortran compilers
^[2]	FASTA format sequence file
	FASTA format amino acid
FACTOR	Factor source file
	FASTA format sequence file
	FASTQ format sequence file
	Forth language block file	Forth development systems
^[3]	FictionBook e-book 2.0 file (DRM-free XML format)	e-book readers
^[4]	3D model geometry, material textures, lighting, armature, and animation sequences for inter application use/transport	Autodesk
FCHK	Gaussian-formatted checkpoint file. Used to store result of quantum chemistry calculation results.^[5]
FCS	FCS molecular biology format.^[6]
^[7]		Chess applications -text data describes a specific position.
	Farbfeld image
FFAPX	FrontFace plugin file	FrontFace digital signage software
^[8] ^[9]	FASTA format nucleotide of gene regions
	CurvFit Input file format	CurvFit software
^[10] ^[11]	Flexible Image Transport System	astronomy software
^[12]	Audio codec, Audio file format
	Fractal configuration file	Apophysis
	FL Studio project file	FL Studio
^[13]	A container format for Flash Video (see also SWF)	Adobe Flash
FMU	A Functional Mockup Unit (FMU) implements the Functional Mockup Interface (FMI).^[14]
	FASTA format nucleic acid
	FileNet Native Document	FileNet
	Saved notes with formatting in markup language	FeatherNote
FODG^[15]	OpenDocument Flat XML Drawings and vector graphics	OpenDocument, LibreOffice, Collabora Online
FODP	OpenDocument Flat XML Presentations	OpenDocument, LibreOffice, Collabora Online
FODS	OpenDocument Flat XML Spreadsheets	OpenDocument, LibreOffice, Collabora Online
	OpenDocument Flat XML Text Document	OpenDocument, LibreOffice, Collabora Online
	Fortran language source file	many
^[16]	Fauna Query Language source file	Fauna
	Match-n-Freq (TM) Input file format	Match-n-Freq software
FRAG	Fragment File, usually stored on MOVPKG files	MOVPKG
^[17]	MySQL Database Metadata	MySQL
	Match-n-Freq (TM) version 7+ Input file format	Match-n-Freq software
	F# source file	F# compilers
	Forth language source code file (often used to distinguish from .fb)	Forth development systems
	Forth language source code file	Forth development systems

G

Ext.	Description	Used by
^[18]	ANTLR4 grammar	ANTLR4
G6	Graph6 graph data format. Used for storing undirected graphs.^[19]
GB	GenBank molecular biology format.^[20]
GBK	same as GB
^[21]	Gerber format	PCB CAD/CAM
^[22]	General Data Format for Biomedical Signals	Biomedical signal processing, Brain Computer Interfaces
	Gerätedatentransfer, an xDT application	Healthcare providers in Germany
^[23]	GEDCOM	Genealogy data exchange
GEOJSON	GeoJSON is specified by RFC 7946.^[24]
GEOTIFF	Used for archiving and exchanging aerial photography or terrain data.^[25]
	GeoGebra File	GeoGebra
^[26]	Compuserves' Graphics Interchange Format (bitmapped graphics)	QPeg - Display - CompuShow
GM9^[27]	Scripts for GodMode9	Godmode9
GMI	Gemtext markup language^[28]	Gemini (Protocol)
GMK	GameMaker Project File	YoYo Games
	Geography Markup Language File	Geography Markup Language
GML	Used for the storage and exchange of graphs. Native format of the Graphlet graph editor software.^[29]
	Go source code file	Go (Programming language)
^[30] ^[31]	GPS eXchange Format
GRAPHML	GraphML is an acronym derived from Graph Markup Language. Represents typed, attributed, directed, and undirected graphs.^[32]
GRB	Commonly used in meteorology to store historical and forecast weather data. Represents numerical weather prediction output (NWP).^[33]
GREXLI	Uncompressed folder as a file	WinGrex/GrexliLib
GRIB	same as GRB
GRP		Duke Nukem 3D
	Generic sensor format	Used for storing bathymetry data, such as that gathered by a multibeam echosounder.
^[34]	Gene transfer format
^[35]	Graph Visualization	Graphviz
GW	same as .lgr. See LGR below for details on LEDA (.gw, .lgr).
GXL	GXL is an acronym derived from Graph Exchange Language. Represents typed, attributed, directed, and undirected graphs.^[36]
GZ	gzip compressed data	gzip

H

Ext.	Description	Used by
	On-line help file	Flambeaux Help! Display Engine
	Pertext database	HELP.EXE
	C-- language header	Sphinx C--
	Header file (usually C language)	Watcom C/C++
	Header file	C++
	Archive	HA
	Source file for the programming language hack	The HHVM^[37]
^[38]	HTTP Archive format (JSON-format web-browser log)	W3C draft standard
HDF	General-purpose format for representing multidimensional datasets. Developed by the US National Center for Supercomputing Applications (NCSA).^[39]
HDF5	General-purpose format for representing multidimensional datasets and images. Incompatible with HDF Version 4 and earlier.^[40]
HDI	Hard Disk Image file (PC-9800 disk image file)	PC-9800 emulators
	heap dumpfile
HEIC	HEIF raster image and compression format. Commonly used for storing still or animated images.^[41]
HEIF	same as HEIC.
	C++ header file
HIN	HyperChem HIN format. Used in cheminformatics applications and on the web for storing and exchanging 3D molecule models. Maintained by HyperCube, Inc.^[42]
	Basic Configuration file	OMSI The Bus Simulator
HOI4	Hearts Of Iron 4 file	Hearts Of Iron 4 Save game
	C++ header file	Zortech C++ - Watcom C/C++
	HTML Application	Microsoft Windows
	see HTML
^[43]	Hypertext Markup Language (WWW)	Netscape - Mosaic - many
	3D Model database	OMSI The Bus Simulator
	C++ header file

I

Ext.	Description	Used by
ICAL	same as ICS (see below).
^[44]		Color Configuration for color input or output devices
	LHA Archive	Cracked LHA (old LHA), Total Commander
	Icon library	Microsoft Windows
ICNS	Macintosh icons format. Raster image file format.^[45]
	Icon file	ICONEDIT.EXE; Microsoft Windows
ICS	ICS iCalendar format. Used for the storage and exchange of calendar information. Commonly used in personal information management systems.^[46]
IFB	Same as ICS (see above).
^[47]	Industry Foundation Classes (platform neutral, open file format used by BIM software). It is registered by ISO and is an official International Standard ISO 16739-1:2018.	BIM software
^[48]	Flight tracks downloaded from GPS devices in the International Gliding Commission's prescribed format
^[49]	Initial Graphics Exchange Specification
IMG	Disk image
	Texinfo hypertext document	Texinfo, info (Unix), Emacs
INI^[50]	Configuration file
^[51]	Archive	CPIO
	XnView IPTC template	XnView, XnViewMP
IPTRACE	AIX iptrace captures^[52] dualhome.iptrace (AIX iptrace) Shows Ethernet and Token Ring packets captured in the same file.^[53]	WireShark
IRX	"IOP Relocatable eXecutable". Library files to dynamically link application code to the Input/Output Processor on the PS2 to communicate with devices like memory cards, USB devices, etc.	Sony PlayStation 2
	ISO-9660 table	see: List of ISO image software
	Impulse Tracker music file	Impulse Tracker

J

Ext.	Description	Used by
	Julia script file	Julia (programming language)
^[54]	JPEG 2000 image	JPEG 2000
J2K	JPEG2000 raster image and compression format. Can store images as an array of rectangular tiles that are encoded separately.^[55]
^[56]	Java archive	JAR, Java Games and Applications
	see JAVA
^[57]	Java source code file
^[58] ^[59] ^[60]	Joint Bilevel Image Group
JCM	same as JDX (see below).
JDX	Chemical spectroscopy format. JCAMP is an acronym derived from Joint Committee on Atomic and Molecular Physical Data.^[61]
^[62]	Java Network Launching Protocol	Java Web Start
	JPEG 2000 image
	Joint Photographic Experts Group graphics file format	Minolta/Konica Minolta cameras use this for JPEGs in Adobe RGB color space
^[63]	Joint Photographic Experts Group graphics file format	QPeg - FullView - Display
	Joint Photographic Group	various (Minolta/Konica Minolta cameras use this for JPEGs in sRGB color space)
^[64]	JavaScript file	script in HTML pages
^[65] ^[66]	JSON (JavaScript Object Notation)	Ajax
^[67]	Jakarta Server Pages	Dynamic pages running Web servers using Java technology
JVX	JavaView 3D geometry format. The native format of the JavaView visualization software. Used for the visualization of 2D or 3D geometries. Can be embedded in web pages and viewed with the JavaView applet.^[68]
	JPEG XL raster graphics file

K

Ext.	Description	Used by
KEY	Keynote Presentation	Keynote
KLC^[69]	MSKLC Source file	Microsoft Keyboard Layout Creator
^[70] ^[71]	Keyhole Markup Language	Google Earth
	Keyhole Markup Language (Zip compressed)	Google Earth
KO	Linux kernel module format system file	Linux
KRA^[72]	Krita image file	Krita
KRABER	Kraber source code file	Kraber Programming Language
	Kornshell source file	Kornshell
KT	Kotlin source code file	Kotlin Programming Language
KV	Kivy

L

Ext.	Description	Used by
LABEL	Dymo label file	Dymo desktop software
LATEX	LaTeX typesetting system and programming language. Commonly used for typesetting mathematical and scientific publications.^[73] ^[74]
	.LBR Archive	for CP/M and MS-DOS using the LU program
	.LDB Leveldb data file	Google key-value storage library
	.LDB MDB Database lock file	Microsoft Access Database
	Labordatenträger, an xDT application	Healthcare providers in Germany
LGR	LEDA graph data format. Commonly used exchange format for graphs. Stores a single, typed, directed, or undirected graph. Native graph file format of the LEDA graph library and the GraphWin application. LEDA is an acronym for Library of Efficient Datatypes and Algorithms.^[75]
	LHA Archive	LHA/LHARC, Total Commander
	LISP source code file
	LLVM Assembly Language	llvm
LM	Language Model File^[76]	Microsoft Windows
LMD	FCS molecular biology format.
	Local file shortcut	Microsoft Windows
LOGICX	Logic Pro files	Logic Pro (MacOS, iPadOS)
LRC	Lyrics file	Lyrics for karaoke-related system and program
	Lua script file	Lua (programming language)
LWO	Native format of the LightWave 3D rendering and animation software. LWO is an acronym for LightWave Object. Developed by NewTek. Stores 3D objects as a collection of polygons and their properties.^[77]
	Archive	Lzip

See also

• List of filename extensions
• List of file formats

External links

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

Notes and References

1. Web site: F4V/FLV Technology Center . 2020-09-15. Adobe.
2. Web site: Alignment Fileformats . 22 May 2019 . 22 May 2019 .
3. Web site: FictionBook 2.0 Specification . 2020-09-13 . bribuser.ru.
4. Web site: Autodesk FBX Files 3ds Max Autodesk Knowledge Network. knowledge.autodesk.com. en-US. 2018-07-28.
5. Web site: FCHK (.fchk) .
6. Web site: FCS (.fcs, .lmd) .
7. Web site: 12 March 1994. Standard: Portable Game Notation Specification and Implementation Guide. 25 July 2020. Internet Archive. The page linking to the document is here.
8. Lipman DJ, Pearson WR . Rapid and sensitive protein similarity searches . Science . 227 . 4693 . 1435–41 . March 1985 . 2983426 . 10.1126/science.2983426 . 1985Sci...227.1435L .
9. Pearson WR, Lipman DJ . Improved tools for biological sequence comparison . Proceedings of the National Academy of Sciences of the United States of America . 85 . 8 . 2444–8 . April 1988 . 3162770 . 280013 . 10.1073/pnas.85.8.2444 . 1988PNAS...85.2444P . free .
10. Web site: Flexible Image Transport System: a new standard file format for long-term preservation projects?. Vatican City. 2012-07-05. 2013-03-06. 2013-05-30. https://web.archive.org/web/20130530040016/http://www.vaticanlibrary.va/moduli/Allegrezza_EWASS2012.pdf. dead.
11. Web site: IAU FITS Working Group. NASA.
12. Web site: FLAC - format . 4 April 2013. Josh . Coalson . "fLaC", the FLAC stream marker in ASCII, meaning byte 0 of the stream is 0x66, followed by 0x4C 0x61 0x43.
13. Web site: Video File Format Specification Version 10. 2020-09-15 . November 2008 . Adobe.
14. Web site: FMU (.fmu) .
15. Web site: 2021-04-27. Open Document Format for Office Applications (OpenDocument) Version 1.3. Part 3: OpenDocument Schema. 2021-09-12. OASIS Open.
16. Web site: Fauna Query Language. 2022-01-26 . fauna.com .
17. Web site: MySQL .frm File Format . 2020-09-13 . mysql.com .
18. Web site: Collection of Antlr4 grammars . .
19. Web site: Graph6 (.g6) .
20. Web site: GenBank (.gb, .gbk) .
21. Web site: Gerber Format . 2020-04-09 . 2020-09-13 . ucamco.com .
22. Schlögl. Alois. GDF - A general dataformat for biosignals. cs/0608052v10. 2006.
23. Web site: GEDCOM X Specifications . 2020-09-14 . gedcomx.org.
24. Web site: GeoJSON (.geojson) .
25. Web site: GeoTIFF (.tif, .tiff) .
26. Web site: Graphics Interchange Format, Version 89a . 31 July 1990 . . 6 March 2009.
27. Web site: Homebrew . Nintendo . GodMode9 Usage . 2023-11-10 . 3DS Hacks Guide . en.
28. Web site: Project Gemini. 2021-11-24. gemini.circumlunar.space.
29. Web site: Graphlet (.gml) .
30. Web site: GPX: the GPS Exchange Format . 2020-09-14 . topografix.com.
31. Web site: OpenGIS Geography Markup Language (GML) Encoding Standard . 2011-03-25.
32. Web site: GraphML (.graphml) .
33. Web site: GRIB (.grb, .grib) .
34. Web site: GTF2.2: A Gene Annotation Format . 2020-09-14 . wustl.edu . 2022-01-19 . https://web.archive.org/web/20220119053409/https://mblab.wustl.edu/GTF22.html . dead .
35. Web site: Graphviz - Graph Visualization Software . 2020-10-20 . graphviz.org.
36. Web site: GXL (.gxl) .
37. Web site: HHVM 4.0.0 . HHVM.
38. Web site: HTTP Archive (HAR) format. W3C Web Performance Working Group. 2012-08-14. 2019-05-18.
39. Web site: HDF (.hdf) .
40. Web site: HDF5 (.h5, .hdf5) .
41. Web site: HEIF (.heic, .heif) .
42. Web site: HIN (.hin) .
43. Web site: HTML Standard . 2020-09-14 . whatwg.org.
44. Web site: ICC Specifications . 2020 . 2020-09-14.
45. Web site: ICNS (.icns) .
46. Web site: ICS (.ics, .ical, .ifb) .
47. Web site: Certified Software. 23 June 2022 .
48. Web site: IGC Flight Recorder Specification Edition 2 with AL5 2019-10-30 . 3 August 2017 . 2020-04-30 . https://web.archive.org/web/20190508035127/https://www.fai.org/page/igc-approved-flight-recorders . 2019-05-08.
49. https://nvlpubs.nist.gov/nistpubs/Legacy/IR/nbsir80-1978.pdf Initial Graphics Exchange Specification IGES Version 1.0
50. Web site: Archiveddocs. Configure an Ini File Item. 2020-12-18. docs.microsoft.com. 22 February 2013 . en-us.
51. https://www.gnu.org/software/cpio/cpio.html "Cpio"
52. Web site: 5.2. Open Capture Files .
53. Web site: SampleCaptures .
54. Web site: Joint Photographic Experts Group, JPEG2000 . JPEG . 2009-11-01 .
55. Web site: JPEG2000 (.jp2, .j2k) .
56. Web site: JAR File Specification . 2020-09-14 . Oracle Corporation.
57. Web site: Gosling, James. Joy, Bill. Steele, Guy. Bracha, Gilad. The Java Language Specification, 2nd Edition. February 8, 2008. https://web.archive.org/web/20110805051057/http://java.sun.com/docs/books/jls/second_edition/html/intro.doc.html#237601. August 5, 2011 . live . mdy-all.
58. Web site: ISO/IEC JTC 1/SC 29/WG 1 - Coding of Still Pictures (SC 29/WG 1 Structure) . ISO/IEC JTC 1/SC 29 . 2009-05-07 . 2009-11-11 . dead . https://web.archive.org/web/20131231055215/http://kikaku.itscj.ipsj.or.jp/sc29/29w12901.htm . 2013-12-31 .
59. Web site: Programme of Work, (Allocated to SC 29/WG 1) . ISO/IEC JTC 1/SC 29 . 2009-11-07 . dead . https://web.archive.org/web/20131231012300/http://kikaku.itscj.ipsj.or.jp/sc29/29w42901.htm . 2013-12-31 .
60. Web site: JTC 1/SC 29 - Coding of audio, picture, multimedia and hypermedia information . ISO . 2009-11-11.
61. Web site: JCAMP-DX (.jdx, .dx, .jcm) .
62. Web site: JSR 56: Java Network Launching Protocol and API . 2020-09-14.
63. Web site: T.81 – DIGITAL COMPRESSION AND CODING OF CONTINUOUS-TONE STILL IMAGES – REQUIREMENTS AND GUIDELINES . . September 1992 . 12 July 2019.
64. Web site: ECMAScript 2020 Language Specification.
65. Web site: Standard ECMA-404 - The JSON Data Interchange Syntax . Ecma International . December 2017 . 27 October 2019 . 1, footnote .
66. Web site: ISO/IEC 21778:2017. ISO. 29 July 2019. subscription.
67. Web site: JSR 245: JavaServer Pages 2.1 . 2020-09-14 . 2013-06-12 . jcp.org.
68. Web site: JVX (.jvx) .
69. Web site: 26 April 2023 . MSKLC Guide . live . https://web.archive.org/web/20230426013150/https://msklc-guide.github.io/ . 26 April 2023 . 26 April 2023 . MSKLC Guide.
70. Web site: OGC Approves KML as Open Standard . OpenGeospatial.org . 2008-04-14 . 2018-11-20.
71. Web site: KML . OpenGeospatial.org . 2018-11-20.
72. Web site: Krita Features. 2022-01-16. krita.org.
73. Web site: LaTeX (.tex) .
74. Web site: Listing of All Formats .
75. Web site: LEDA (.gw, .lgr) .
76. Web site: LM file - What is an LM file and how do I open it? . fileinfo.com . 12 August 2023.
77. Web site: LWO (.lwo) .