Everyone has had the ex­pe­ri­ence of en­coun­ter­ing file ex­ten­sions they did not know at some point or other. You might im­me­di­ate­ly recognize the common ones like JPG or MP3 and know that it is either an image file or a music file, re­spec­tive­ly. However, in addition to these well-known filename ex­ten­sions, there are countless others that users may not recognize. Naturally, it does not help that new file ex­ten­sions are con­stant­ly being added to the pool of existing ones.

In the following article, we will provide a list of the most important file ex­ten­sions for text, image, video, and various other digital files.

What is a file extension?

A file extension (also known as a filename extension, file type, or file suffix) is the last part of a file name. This element is separated from the actual file name by a dot and typically consists of three to four char­ac­ters. The file extension can be used to identify the type of file format as well as which ap­pli­ca­tions can be used to open and edit the file.

For example, a PDF file is a Portable Document Format file which can be opened with programs such as Adobe Reader. Since file ex­ten­sions are not stan­dard­ized, it is possible for one extension to be used for different file types. Some operating systems hide file ex­ten­sions so that in­ex­pe­ri­enced users cannot ac­ci­den­tal­ly modify them.

The most common file ex­ten­sions in a list

In the following sections, we have provided tables sum­ma­riz­ing the most important ex­ten­sions for various types of computer files such as images, text documents, videos, and system files.

File ex­ten­sions for image files

Extension De­scrip­tion Format
.bmp BMP (also called bitmap) is a two-di­men­sion­al raster graphics format developed for Microsoft and IBM operating systems. Graphics format
.gif GIF (Graphics In­ter­change Format) is a special graphics format for images, an­i­ma­tions, and short clips. Graphics format
.heif, .heic HEIF (High Ef­fi­cien­cy Image Format File) is a container format that can combine any number of images in one file to save space. Graphics format
.jpg, .jpeg The JPEG format (Joint Pho­to­graph­ic Experts Group) is one of the most common graphics formats. It has a com­par­a­tive­ly small file size while main­tain­ing high image quality. Graphics format
.png PNG stands for Portable Network Graphics and is a commonly used graphics format with lossless data com­pres­sion. Graphics format
.psd PSD (Photoshop Document) is the standard format for files created with Adobe Photoshop. Graphics format
.svg The SVG file extension (Scalable Vector Graphics) iden­ti­fies files with two-di­men­sion­al vector graphics. Graphics format
.tif, .tiff TIFF (or TIF) stands for Tagged Image File Format. This graphics format is con­sid­ered the standard for storing high-res­o­lu­tion photos and print data. Graphics format
Tip

We go over the most important image formats in more detail in one of our feature articles.

File ex­ten­sions for text files and other documents

Extension De­scrip­tion Format
.doc, .docx These are the two file ex­ten­sions for Microsoft Word text documents. In addition to text, these files can also contain images and graphics. Text file
.md MD (Markdown Doc­u­men­ta­tion) is a format for plain text documents without any ad­di­tion­al elements. Text file
.odt The extension ODT (Open­Doc­u­ment Text) iden­ti­fies text documents created with the free-to-use office software suite Apache OpenOf­fice. Text file
.pdf Adobe’s PDF file extension (Portable Document Format) is probably the most commonly used file format across the Internet. PDFs can contain text, images, graphics, videos, and audio. Document format
.ppt, .pptx PPT and PPTX, which were in­tro­duced in 2007, are file ex­ten­sions for editable files created in the popular Microsoft pre­sen­ta­tion program Pow­er­Point. Pre­sen­ta­tion file
.rtf RTF (Rich Text Format) is a file format that enables text to be shared between programs in different operating systems. Text file
.txt The TXT file extension iden­ti­fies plain text documents that contain no for­mat­ting or images. Text file
.xls, .xlsx XLS and XLSX identify files created in the Microsoft spread­sheet program Excel. Spread­sheet file
Tip

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Audio files

Extension De­scrip­tion Format
.flac FLAC (Free Lossless Audio Codec) is a format for free lossless audio com­pres­sion. Audio file
.mp3 MP3 (MPEG Audio Layer 3) is the best known and most widely used format for audio files. Audio file
.aac The audio file format AAC (Advanced Audio Coding) is designed to be the successor to the MP3 format. Audio file
.ogg OGG is a container format for mul­ti­me­dia files. Container format
.wma WMA (Windows Media Audio) is a com­pressed audio format. Audio file
.wav, .wave WAVE (Waveform Audio File Format) is a container format for the lossless storage of audio files. Audio file

Video files

Extension De­scrip­tion Format
.avi AVI (Audio Video In­ter­leave) is a video container format created by Microsoft. Video format
.flv FLV (Flash Video) iden­ti­fies an open container file format that is primarily used for sending video content over the Internet. Video format
.mov MOV is a file format developed for Apple’s QuickTime Player. Video format
.mp4 MP4 is a modern video format designed for MPEG-4 content. Video format
Tip

You can learn more about the most important video formats in our feature article.

System files

Extension De­scrip­tion Format
.dll The file extension DLL (Dynamic Link Library) iden­ti­fies dynamic software libraries. System file
.drv DRV files (driver files) enable com­mu­ni­ca­tion between computers and hardware devices. Driver file
.ini INI is a con­fig­u­ra­tion file for ini­tial­iz­ing program settings. Ini­tial­iza­tion file
.tmp The TMP file extension iden­ti­fies au­to­mat­i­cal­ly generated files that tem­porar­i­ly store data. Temporary file

Com­pressed data files

Extension De­scrip­tion Format
.7z 7z is a free file format for archiving files. Archive file
.jar JAR (Java Archive) is a zip file that has a library con­tain­ing multiple files. Archive file
.rar A RAR file is a com­pressed file, or data container, that holds one or more files or folders. Archive file
.zip ZIP is probably the most popular file format for com­press­ing files. Archive file

Ex­e­cutable files

Extension De­scrip­tion Format
.bat BAT (batch file) is a script file con­tain­ing a series of ex­e­cutable commands. Batch file
.com The COM file extension (command) iden­ti­fies ex­e­cutable programs in MS-DOS. Ex­e­cutable file
.exe The EXE file extension iden­ti­fies ex­e­cutable ap­pli­ca­tions in Windows-based systems. Ex­e­cutable file

File ex­ten­sions for web file formats

Extension De­scrip­tion Format
.css CSS stands for Cascading Style Sheets and is used for website design. Stylesheet language
.html HTML (Hypertext Markup Language) is a text-based markup language. Document format
.js JavaScript is a scripting language for websites. JavaScript code file
.php PHP (Hypertext Pre­proces­sor) is a scripting language for web ap­pli­ca­tions, which is widely used around the world. Script file
.xml XML (Ex­ten­si­ble Markup Language) is a text-based markup language. Document format

Email files

Extension De­scrip­tion Format
.eml EML is the file extension for text-based emails. Email file
.msg MSG is the file extension for emails in Microsoft Outlook. Email file
.ost An OST file is an offline Microsoft Outlook data file with locally stored data. Data file
.pst A PST file is a Microsoft Outlook data file con­tain­ing personal in­for­ma­tion. Container file
Tip

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