File Extensions, Formats, and Utilities

Common Mac/PC File Extensions
and Programs that may Open them

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

File Extension	Format Description and Type	How to deal with it
.123	Lotus 123 File	Use Lotus123 or another spreadsheet with a conversion utility
		Use Lotus123 or another spreadsheet with a conversion utility.
		Use Lotus 123 or another spreadsheet with a conversion utility. Excel Viewer may also be able to open these files.
.aac	Advanced Audio Coding (AAC) is an audio-specific compression format.	Use QuickTime or iTunes
		Use iTunes for Windows
		Use iTunes for Windows
.arc	Macintosh Hierarchical Archive	Download as MacBinary, and launch it. Self Extracting
		N/A
		Use Stuffit Expander for Windows
.aiff	.aiff is a sound format commonly used on the Mac Platform.	Use Quicktime to play it
		Use QuickTime for Windows or use Waveform Hold and Modify to play it
		Use QuickTime for Windows or use Waveform Hold and Modify to play it
.ai .art	Adobe Illustrator and also may be a Clip Art file.	Use Adobe Illustrator
		Use Adobe Illustrator
		Use Adobe Illustrator
.asp	Probably an Active Server Page. This is a server side customized html page.	View it in your browser
		View it in your browser
		View it in your browser
.au	.au is a once common sound format found on the web.	Use Sound Player to play it
		Use Waveform Hold and Modify to play it
		Use Waveform Hold and Modify to play it
.avi	Audio Video Interleaved - Windows movie file	Use Quicktime to play it
		Use Windows Media Player
		Use Windows Media Player
.bat	DOS batch file. A series of line commands, similar to a shell script. To run, simply name the file at the command line. AUTOEXEC.BAT runs when you boot your pre win2000 PC.	Use any text editor
		Use any text editor
		Use any text editor WordView
.bin	Macbinary II Encoded File. Make sure to download as MacBinary or Binary.	Use Stuffit Expander to turn back into a usable Macintosh file if it isn't already.
		N/A
		N/A
.cgi	A cgi script. Common Gateway Interface. Probably written in C but maybe Perl. If it is in C and compiled, then you probably can't edit it. You will know right away when you try to open it in a text editor	Use any text editor
		Use any text editor
		Use any text editor WordView
.dat	Generally a data file, written by an application.	Use Microsoft Word, Simple Text, BBEdit, or any text editor.
		Open in Notepad or any text editor.
		Open in Notepad or any text editor.
.dbx	May be a Microsoft Visual Foxpro table file	n/a
		Use Foxpro or import to other relational database
		Use Foxpro or import to other relational database
.dll	Dynamic Link Library. This is a compiled set of procedures and/or drivers called by another program	n/a
		compiled file - do not move or alter
		compiled file - do not move or alter
.dmg	Macintosh Disk Image, most commonly found on Apple's FTP sites.	Use Disk Utility or Intaller
		N/A
		N/A
.doc .dot	May be a Microsoft Word or Wordpad Document. .dot is a Microsoft Word Template	Use MS-Word
		Use WordView to quickly display MS-Word documents
		Use WordView to quickly display MS-Word documents
.eml	May be an Outlook Express saved message. This extension is assigned when you choose file\|save in Outlook.	use a text editor
		Use Outlook or a text editor
		Use Outlook or a text editor
.exe	May be a DOS/Windows program or a DOS/Windows Self Extracting Archive	You need to run this in a DOS/Windows emulator such as RealPC
		Download and launch it in its own temporary directory, it may spawn a number of files and directories. Self Extracting
		Download and launch it in its own temporary directory, it may spawn a number of files and directories. Self Extracting
.gif	GIF (Graphical Interchange Format), though not the most economical, is the most common graphics format found on the Internet.	Use GIFConverter or JPEG View
		Use Lview Pro to view these graphics
		Use PolyView to view these graphics
.gz	.gz is the Gnu version of zip. It is a compression method developed for use on UNIX systems.	Use macgzip to view and extract archives.
		Use WinZIP to view and extract archives.
		Use WinZIP to view and extract archives.
.hlp	This is a Windows help file. Windows provides some annotating features to modify the file but as they are compiled files, they cannot be edited without a great deal of difficulty.
		Use Helpmaker Plus to create your own help files.
		Use Helpmaker Plus to create your own help files.
.html .htm	HTML (Hypertext Markup Language), the code of simple web pages. Plain text file.	Use Safari, Explorer, Firefox or Netscape for MacIntosh to view the file
		Use Explorer, Firefox or Netscape for Windows 3.1x to view the file
		Use Netscape for Windows95 and Windows NT to view the file
.hqx	BinHex 4.0 - Encodes a Macintosh file into 7-bit text so it can be safely transfered. Most Mac files appear in .hqx	Use Stuffit Expander
		Use BinHex13 in a DOS window to un-binhex it
		Use BinHex13 in a DOS window to un-binhex it
.image .img	Macintosh Disk Image, most commonly found on Apple's FTP sites.	Use Shrink Wrap to mount the disk image, and deal with it like you would a floppy
		N/A
		N/A
.ini	Initialization file. Typically earlier windows, but still used. These are software settings, and environment variables. You can tweak them with a text editor, but keep a backup!	N/A
		Use Use any text editor
		Use Use any text editor
.jpg .jpeg .jfif	JPEG/JFIF, a 24 bit graphic format	Use JPEG View
		Use Lview Pro to view these graphics
		Use PolyView to view these graphics
.lwp	Lotus WordPro File	N/A
		Use Lotus WordPro
		Use Lotus WordPro or Quick View Plus
.max	May be a Paperport file	Use Paperport Viewer
		Use Paperport Viewer
		Use Paperport Viewer
.mdb .mde	Microsoft Access Database	Use Microsoft Access
		Use Microsoft Access
		Use Microsoft Access
.mim .mime	Multi-Purpose Internet Mail Extensions.	Use your email client or a text editor
		Use your email client or a text editor
		Use your email client or a text editor
.mp3	MP3 is an audio-specific compression format.	Use QuickTime or iTunes
		Use Windows Media Player
		Use Windows Media Player
.mpg .mpeg	MPEG, a standard internet movie platform.	Use QuickTime or sparkle
		Use VMPEG with win32s to play MPEGs
		Use VMPEG or Ladybug to play MPEGs
.mov .qt .movie .moov	QuickTime Movie, Apple Macintosh native movie platform	Use QuickTime or sparkle
		Use QuickTime for Windows
		Use QuickTime for Windows
.pdf	Adobe Acrobat Portable Document Format, download as Binary	Use Adobe Acrobat Reader or Adobe Acrobat
		Use Adobe Acrobat Reader or Adobe Acrobat
		Use Adobe Acrobat Reader or Adobe Acrobat
.pfc	AOL Personal File Cabinet	Manage from inside AOL
		Manage from inside AOL
		Manage from inside AOL
.pl	Perl Script. Runs on UNIX type platforms. ASCII File.	Use any text editor
		Use any text editor
		Use any text editor
.pps .ppt	.pps may be Microsoft Powerpoint Slide Show, .ppt may be Microsoft PowerPoint Presentation	Use Microsoft PowerPoint
		Use Microsoft PowerPoint
		Use Microsoft PowerPoint
.ps	Postscript file. Plain text file, but not really human-readable.	Send to a Postscipt printer with Laserwriter Font Utility or view it onscreen using Ghostscript
		View it onscreen using Ghostscript
		View it onscreen using Ghostscript
.pub	May be Microsoft Publisher Document	Use Microsoft Publisher. If anyone knows of a viewer, let me know.
		Use Microsoft Publisher. If anyone knows of a viewer, let me know.
		Use Microsoft Publisher. If anyone knows of a viewer, let me know.
.rtf	Rich Text Format	Use any word processor or editor with features
		Use Wordpad
		Use Wordpad
.rm	Real Movie	Download RealPlayer
		Download RealPlayer
		Download RealPlayer
.sit	Stuffit Archive - Binary	Use Stuffit Expander
		Use UnSit in a DOS window
		Use Stuffit Expander for Windows
.sea	Macintosh Self Extracting Archive	Download as MacBinary, and launch it. Self Extracting
		N/A
		Use Stuffit Expander for Windows
.smi	Shrink Wrap Disk Image File	Use ShrinkWrap
		N/A
		N/A
.swp	This is probably a Win95 "swap" file where windows swaps out infomation from memory to the disk. You should not mess with this file. If it is over 200 megs, look into "swap space" in your windows configuration	N/A
		N/A
		N/A
.sys	Probably a DOS/Windows system file; You should only edit these if you know exactly what you are doing	N/A
		Use any text editor
		Use any text editor
.tar .tar.Z .tar.gz .tgz	UNIX tar program takes separate files and turns them into one file - often also compressed. Extensions such as .tar.Z, .tar.gz and .tgz (latter two are equivalent) requires decompression first, then un-tar. Some UNIX ftp servers will un-tar a file if you request it without the ".tar" extention.	Download and use Tar
		Use WinZIP to view and extract archives.
		Use WinZIP to view and extract archives.
.tiff .tif	TIFF is a very large high quality image format.	Use Adobe Photoshop or JPEGView
		Use Lview Pro to view these graphics
		Use PolyView to view these graphics
.txt	A plain boring old Text File	Use Microsoft Word, Simple Text, BBEdit, or any text editor.
		Open in Notepad or any text editor.
		Open in Notepad or any text editor.
.uu .uue	A uuencoded file. Typically this is done on a UNIX command line: uuencode OriginalFileName SecondFilename > EncodedFile.uu Then, after running: uudecode EncodedFile.uu One gets a file generated named: SecondFileName Using .uu as the extension is not required but is considered politely explanatory for what type of file it is. Increasing numbers of desktop mail and newsreading programs will handle this type of encoding on the fly.	Use UU Undo to uudecode it
		Use WinCode to uudecode it
		Use ESS-Code to uudecode it
.vsd	Visio Drawing File.	Use OmniGraffle
.vsd	Visio Drawing File.	Use Visio
.wav	Windows Wave format sound file	Use QuickTime orSoundApp to play .wav files
		Use Waveform Hold and Modify to play it
		Use Waveform Hold and Modify to play it
.wk1 .wk3 .wk4	Lotus Worksheets. Can often be converted by Excel.	Use Lotus
		Use Lotus
		Use Lotus
.wpd	WordPerfect Document	Use WordPerfect
		Use WordPerfect
		Use WordPerfect
.xls .xlw .xlt	Microsoft Excel Spreadsheet, Excel Workbook, Excel Template	Use Microsoft Excel
		Use Microsoft Excel
		Use Microsoft Excel or Excel Viewer depending on the version.
.Z	Unix Compressed File	If you are downloading via ftp most ftp servers will uncompress for you if you drop the ".Z". Otherwise use Stuffit Expander w/EE.
		Use WinZIP to view and extract archives.
		Use WinZIP to view and extract archives.
.zip	pkzip, a common DOS/Windows compression format	Use ZipIt, Stuffit Expander w/ EE, or MacUnZip
		Use WinZIP to view and extract archives.
		Use WinZIP to view and extract archives.

Where to get the Software packages

Adobe Acrobat Reader: Freeware program from Adobe to read Adobe Acrobat Portable Document Format files.
BinHex13: Use this in a DOS window to get the original file.
ESS-Code: A Windows 32 bit program. Allows drag and drop uuencoding/decoding and MIME support. Look for tile name like ecdXXw95.zip where XX is a version number
Ghostscript: Freeware program for viewing Postscript files on screen, saving to PICT format, etc. The program requires that you install a large (~6 MB) collection of files though. It also crashes alot.
GIFConverter: Shareware program (~$30) for viewing and converting between GIF, PICT, TIFF, RLE, JPEG (JFIF), EPSF, RIFF, Macpaint, StartupScreen and "Scan Image" formats. Some primitive file editing can be done such as cropping and re-sizing (scale-by-percent) and adjusting file resolution and dither pattern. GIFConverter will save GIFs in Interlaced format if you choose, but cannot handle transparent colors.
HelpMaker Plus: Help Maker Plus is a shareware program to easily create your own Windows help files.
JPEGView: JPEGView is a freeware graphic program to read GIF, JPEG, TIFF, and PICT files. Runs fast and will dither nicely to any size of screen/color palette.
Ladybug: The Ladybug 1.00 for Windows95/NT can only play MPEG files less than 800KB but it looks promising, watch for updates.
Laserwriter Font Utility: This comes with your Macintosh. It's on the Printing Tools disk, or it may already be installed in your Utilities folder. If you need to download it from Apple, you can.
Lview Pro: Lviewpro provides support for a variety of graphics formats including GIF '89 (transparent backgrounds), conversion between different formats and image editing functions.
Paperport Viewer: Visioneer's (now ScanSoft's?) Paperport Viewer is freeware.
Netscape: Netscape, although now rather bloated, continues to be the best browser.
PolyView: PolyView is a Windows NT/95 program that displays GIF, JPEG, TIFF, and photo-cd graphics files and converts between these file formats.
Programmer's File Editor: Programmer's File Editor is a large-capacity multi-file programming oriented editor for Windows 3.1x, Windows NT on Intel and PowerPC platforms, and Windows 95. Get the 16 bit version (pfeXXXX.zip) at http://www.winsite.com/
QuickTime: QuickTime is Apple's video format. Players for Macintosh and Windows are available.
RealPlayer: RealPlayer is available from Real.com.
Microsoft Viewers: Microsoft has a number of free viewer downloads including Excel Viewer and others.
Quick View Plus: Quick View Plus is a large viewer with an evaluation download.
Shrinkwrap: Shrinkwrap is a free Mac utility that allows you to mount and use disk image files as if they were a mounted floppy disk. You can also copy disk images to floppies with Shrinkwrap by simply dragging the floppy icon onto Shrinkwrap.
Sound Player: Sound Player is a multipurpose sound program that can record and play back .au and aiff format sounds.
SoundApp: SoundApp is a small featureless program that will play most audio files.
Sparkle: Sparkle is a very good MPEG player for the mac. You can play and convert between Quicktime and MPEG.
Stuffit Expander with Expander Enchancer: Stuffit Expander is the decompression program for the mac. With Expander Enchancer (It is installed when you install DropStuff) you can expand a LOT of formats! Get both Stuff Expander and Drop Stuff w/ EE from Aladdin
Tar: Tar 4.0 will read and write tar files.
UNSIT: UNSIT is a simple utility for PC users to extract files from a StuffIt file.
UU Undo: UU Undo is a simple program to decode uu encoded files on the mac.
VMPEG: VMPEG can play MPEG system layer streams containing both video and audio. This is a win32s program.
Waveform Hold and Modify (WHAM): WHAM provides support for a variety of formats, conversion between them and file editing functions.
WinCode: Wincode is a Windows 3.x program which converts 8-bit BINARY (EXE, COM,GIF, etc) files to 7-bit ASCII (Text) files (and vice versa) through a process known as bit-shifting. Wincode currently supports UU/XX and Base64 (MIME 1.0 conformant) coding.
WinZip: WinZip is an essential tool for its excellent handling of many different archiving and compression formats. Downloads as a self-extracting archive.
WordView: For MS-Windows users, displaying Microsoft Word documents without having to allocate the memory resources required to fire up MS-Word is very handy. Get yours at ftp://ftp.microsoft.com/Softlib/MSLFILES/
ZipIt: A fast program for the Macintosh to extract and create Zip archives.

Common Mac/PC File Extensions and Programs that may Open them

Common Mac/PC File Extensions
and Programs that may Open them