.$$$ - This file extension is used by a variety of computer applications to store temporary computer files. These files are created by the application and usually contain temporary data that frees up the memory being used by the application.
.386 - This file is a read-only file that is copied to the root directory of the startup drive during an MS-DOS 5 or 6 upgrade. It is used for running in "386 enhanced mode."
.AI - It is a proprietary file format developed by Adobe Systems for representing single-page vector-based drawings in either the EPS or PDF formats.
.AIF, AIFF - Audio Interchange File Format is an audio file format standard used for storing sound data for personal computers and other electronic audio devices.
.ANI - This file format is a graphics file format used for animated mouse cursors on the Microsoft Windows operating system.
.ARC - It's an compression format.
.ARJ - ARJ is a software tool designed by Robert K. Jung for creating high-efficiency compressed file archives.
.ASF - ASF is the container format for Windows Media Audio and Windows Media Video-based content. The extension wma or wmv is used to specify an ASF file that contains content encoded with the Windows Media Audio and/or Windows Media Video codecs.
.AU - The Au file format is a simple audio file format introduced by Sun Microsystems. The format was common on NeXT systems and on early Web pages.
.AVI - This extension is a multimedia container format introduced by Microsoft in November 1992 as part of its Video for Windows software. AVI files can contain both audio and video data in a file container that allows synchronous audio-with-video playback.
.AVS - Configuration file used by Advanced Visualization Studio (AVS), an audio visualizer for Winamp; contains settings for animations that are created based on the music played within Winamp.
.BAK - In computing, ".bak" is a filename extension commonly used to signify a backup copy of a file. When a program is about to overwrite an existing file, the program may first make a copy of the existing file, with .bak appended to the filename.
.BAS - BAS is a file extension for a source code file format used by BASIC, an early programming language that is still among the simplest and most popular of programming languages.
.BAT - A batch file is a script file in DOS, OS/2 and Microsoft Windows. It consists of a series of commands to be executed by the command-line interpreter, stored in a plain text file.
.BIN - A BIN file is a file that stores data in a binary format. It is different than a text-based file, which can be edited in a text editor. BIN files may be created by a variety of different programs but typically cannot be manually edited.
.C - A C file is a source code file for a C or C++ program. It may include an entire program's source code, or may be one of many source files referenced within a programming project. C files can be edited using a basic text editor, but will not show syntax highlighting like most software development programs do.
.CAB - Cabinet is an archive-file format for Microsoft Windows that supports lossless data compression and embedded digital certificates used for maintaining archive integrity. Cabinet files have .cab filename extensions and are recognized by their first 4 bytes MSCF. Cabinet files were known originally as Diamond files.
.CDA - It is a common filename extension denoting a small stub file generated by Microsoft Windows for each audio track on a standard "Red Book" CD-DA format audio CD as defined by the Table of Contents.
.CMD, .COM, .EXE - Executable files that consist binary data.
.CPL - A CPL file is a control panel item, such as Displays, Mouse, Sound, or Networking, used by the Windows operating system.
.CSS - CSS is a plain text file format used for formatting content on web pages. CSS stands for Cascading Style Sheet and is used by web pages to help keep information in the proper display format.
.CSV - A comma-separated values file is a delimited text file that uses a comma to separate values. Each line of the file is a data record. Each record consists of one or more fields, separated by commas. The use of the comma as a field separator is the source of the name for this file format.
.CUR - A CUR file is a cursor image or animation used for the Windows mouse pointer. It may be an arrow (for general use), a spinning hourglass (for waiting periods), or an I-bar (for text editing).
.DAT - A DAT file is a generic data file created by a specific application. It may contain data in binary or text format (text-based DAT files can be viewed in a text editor). DAT files are typically accessed only by the application that created them.
.DLL - A DLL file is a compiled library that contains a set of procedures and/or drivers that are referenced and executed by a Windows program. It allows multiple programs to access shared functions through common libraries. DLL files are "dynamically linked" into a program at runtime, meaning they are only loaded when needed.
.DOC - A DOC file is a word processing ******** created by Microsoft Word, or another word processing program, such as OpenOffice Writer or Apple Pages. It may contain formatted text, images, tables, graphs, charts, page formatting, and print settings.
.DOT - A DOT file is a template created by Microsoft Word, a word processing application and may be opened by various word processors. It contains pre-formatted ******** settings, such as headers, footers, margins, font sizes, and other common page styles.
.DRV - A DRV file is a driver file used by Windows operating systems to connect and communicate with hardware devices (both external and internal).
.EPS - An EPS file is a graphics file saved in the Encapsulated PostScript (EPS) file format. It may contain 2D vector graphics, bitmap images, and text. EPS files also include an embedded preview image in bitmap format.
.FLC, .FLI - AutoDesk animation files.
.FNT, .FON, .TTF - Font files.
.HLP - File used by Windows Help, a program provided with Windows that lets users read help information; contains ********ation and indexes for Windows programs or the Windows operating system; compiled using Microsoft Help Workshop (HCW.exe).
.HTM, .HTML - They are HTML webpages used by web browsers, such as Google Chrome, Microsoft Edge, and Mozilla Firefox. It may contain hyperlinks and markup language, which defines the elements and layout of a webpage.
.ICO - Windows icon file.
.INF - An INF file is a plain text configuration file that defines what files are installed with a certain software program or update. It may also list the ******** of the files and the directories where the files are to be installed. INF files are used by the Windows operating system, or by the program or installer that includes the INF file.
.INI - An INI file is a configuration file used by Windows programs to initialize program settings. It contains sections for settings and preferences (delimited by a string in square brackets) with each section containing one or more name and value parameters.
.JPEG, .JPG, .JIF, . JFF, .JFIF - A JPEG file is an image saved in a compressed graphic format standardized by the Joint Photographic Experts Group (JPEG). It supports up to 24-bit color and is compressed using lossy compression, which may noticeably reduce the image quality if high amounts of compression are used. JPEG files are commonly used for storing digital photos and web graphics.
.LOG - A LOG file is a log used by various operating systems and programs. It typically contains a plain text log of certain events with their timestamps. LOG files may be created by the operating system to keep track of system events or by a software installation program to list ******** and names of installed files.
.MDB - Access database file.
.MID - A MID file is a standard MIDI (Musical Instrument Digital Interface) file used by music authoring and mixing programs as well as MIDI hardware devices. It contains music data, such as what notes are played, when they are played, how long each note is held, and how loud each note is played.
.MP3 - An MP3 file is an audio file saved in a compressed audio format developed by the Moving Picture Experts Group (MPEG) that uses "Layer 3" audio compression (MP3). It is most commonly used to store music, but may also contain other types of audio content, such as a lecture, sermon, audiobook, or podcast.
.MPE, .MPEG, . MPG - An MPG file is a common video file that uses a digital video format standardized by the Moving Picture Experts Group (MPEG). It stores video, audio, and ****data interleaved together. MPG files are often used for creating movies that are distributed on the Internet.
.OCX - An OCX file contains a reusable software module, called an ActiveX control, which can be used within Windows software programs. ActiveX controls can be created for various purposes, such as user interface forms, webpage widgets, online games, and multimedia viewers.
.PCX - Raster image format developed by ZSoft; became one of the original bitmap image formats for the DOS/Windows platform; supports 24-bit color images, 8-bit grayscale and indexed color images, and 1-bit black and white images; compressed using RLE encoding.
.PIF - A PIF file contains information used to define how an MS-DOS-based program should run. It can also serve as a shortcut to an executable file, much like a .LNK file, and is commonly created when the user makes a a shortcut to a DOS program or modifies the properties of the program.
.PNG - A PNG file is an image saved in the Portable Network Graphic (PNG) format. It contains a bitmap compressed with lossless compression similar to a .GIF file. PNG files are commonly used to store web graphics, digital photographs, and images with transparent backgrounds.
.PPS - A PPS file is a slide show created by Microsoft PowerPoint, a popular program included with Microsoft Office for creating presentations. It is saved as a completed slide show, which can be viewed by PowerPoint, OpenOffice, and several other presentation programs. PPS files are similar to .PPT files but open as a slide show when double-clicked.
.PPT - A PPT file is an editable slide show created by Microsoft PowerPoint or another presentation program, such as OpenOffice Impress or Apple Keynote. It may include formatted text, bullet points, images, movies, sound effects, and music. PPT files are commonly built from one of many templates included with the PowerPoint software, but may also be created from scratch.
.PSD - A PSD file is an image file created by Adobe Photoshop, a professional image-editing program often used to enhance digital photos and create web graphics. It is the native format used to save files in Photoshop. PSD files may include image layers, adjustment layers, layer masks, annotations, file information, keywords, and other Photoshop-specific elements. They are commonly created and shared among graphics professionals.
.MOV, .QT - QuickTime multimedia formats developed by Apple Computer; cross-platform, meaning it is supported on both Macintosh and Windows systems; may contain a compressed audio and video track.
.RA, .RAM, .RM - An RM file is a multimedia file saved in the RealMedia multimedia container format developed by RealNetworks. It may store only audio in the RealAudio format, only video in the RealVideo format, or both RealAudio and RealVideo. RM files are commonly used for streaming content over the Internet such as video and Internet radio.
.RAR - A RAR file is an archive that contains one or more files compressed with RAR compression. It uses a higher compression ratio than typical ZIP compression and incorporates a proprietary compression algorithm that is now used by other compressors, including 7-Zip for its .7Z files. RAR archives are used to compress files to reduce their size for transportation or storage purposes.
.RAW - A RAW file is an image generated by digital cameras such as Panasonic, Leica, and Casio cameras. It contains uncompressed, raw image data that can be adjusted for exposure and white balance using software that supports the format.
.REG - Windows Registry file. It's a text-based file created by exporting values from the Registry and can also be used to add or change values in the Registry.
.RTF - An RTF file is a common text file format that supports "rich text." It includes several types of text formatting, such as bold type, italics, different fonts and font sizes, and custom tab settings. RTF files also support objects and images, such as .JPG and .PNG files, saved within the text file.
.SIT - Compressed file "stuffed" by Smith Micro StuffIt software; common file compression format used on Macintosh systems; originally Mac-only, now cross-platform, meaning SIT files can be created and opened on both Macintosh and Windows platforms.
.SCR - An SCR file is a screen saver file used by Microsoft Windows. It contains a graphic, animation, slide show, or video that you can use as a Windows screensaver. SCR files are typically stored in Windows's main directory.
.SYS - System files.
.TAR - A TAR file is an archive created by tar, a Unix-based utility used to package files together for backup or distribution purposes. It contains multiple files stored in an uncompressed format along with ****data about the archive. TAR files are commonly compressed into .GZ files with GNU Zip compression.
.THEME - A THEME file contains a theme for Microsoft Plus!, a software enhancement to the Windows operating system. It contains settings used to customize the Windows desktop and is saved in Microsoft's .INI text-based format, which includes colors, styles, and references to image and sound files used by the theme. THEME files may be included with the Microsoft Plus! software or may be custom made by the user.
.TIF, TIFF - A TIF file contains an image saved in the Tagged Image File Format (TIFF), a high-quality graphics format. It is often used for storing images with many colors, typically digital photos, and includes support for layers and multiple pages.
.TMP - Temporary files.
.TXT - A TXT file is a standard text ******** that contains unformatted text. It is recognized by any text editing or word processing program and can also be processed by most other software programs. TXT files are often created and opened using Microsoft Notepad and Apple TextEdit.
.WAB - Address book file that contains contact information, such as names and e-mail addresses; used by Microsoft Outlook Express, a popular free email program; similar to the .PAB file used by the full version of Microsoft Outlook.
.WAV - A WAV file is an audio file saved in the WAVE format, which is a standard digital audio file format utilized for storing waveform data. WAV files may contain audio recordings with different sampling rates and bitrates but are often saved in a 44.1 KHz, 16-bit, stereo format, which is the standard format used for CD audio.
.WMF - Proprietary Windows graphic format developed by Microsoft; contains a series of drawing operations, including commands for drawing lines, circles, and rectangles; may also contain bitmap drawing operations; used primarily for vector images, but can also include raster graphics.
.WRI - A WRI file is a text ******** created with Microsoft Write, a basic word processor that came with early versions of Windows through Windows 3.1. It may contain styled text and page formatting information.
.XLS - An XLS file is a spreadsheet file created by Microsoft Excel or another spreadsheet program, such as OpenOffice Calc or Apple Numbers. It contains one or more worksheets, which store and display data in a table format. XLS files may also store mathematical functions, charts, styles, and formatting.
.Z - Compressed file used to store, or "pack," files on Unix-based machines; incorporates a simple compression algorithm that is used to archive files and save disk space; can be decompressed on a Unix system by typing uncompress filename.z, where "filename.z" is the name of the file to decompress.
.ZIP - A ZIP file is an archive that contains one or more files compressed or "zipped" using Zip compression. It stores files separately from each other allowing the files to be compressed using different methods and extracted without compressing or decompressing the entire archive.