What are the most common file types and file extensions?

There are hundreds of different file extensions and file types used with computers, and you can find a complete list on our computer files and file extensions page. However, it would be impossible for most people to memorize all file extensions and their associated programs. Below is a list of the most common file extensions, broken into categories by type of files.

Audio file formats by file extensions

There are several audio file formats, standards, and file extensions used today. Below is a list of the most common audio file extensions.

• .aif — AIF audio file
• .cda — CD audio track file
• .mid or .midi — MIDI audio file.
• .mp3 — MP3 audio file
• .mpa — MPEG-2 audio file
• .ogg — Ogg Vorbis audio file
• .wav — WAV file
• .wma — WMA audio file
• .wpl — Windows Media Player playlist

Compressed file extensions

Most computer users are familiar with the .zip compressed files, but there are other types of compressed files. Below is a list of the most common compressed file extensions.

Disc and media file extensions

When making an image of a disc or other media, all of the contained files are saved to an image file. Below are the most common disc image file extensions.

• .bin — Binary disc image
• .dmg — macOS X disk image
• .iso — ISO disc image
• .toast — Toast disc image
• .vcd — Virtual CD

Data and database file extensions

A data file could be any file, but for this list, we’ve listed the most common data files that relate to data used for a database, errors, information, importing, and exporting.

E-mail file extensions

Below is a list of the most common file extensions for e-mail and related files.

• .email — Outlook Express e-mail message file.
• .eml — E-mail message file from multiple e-mail clients, including Gmail.
• .emlx — Apple Mail e-mail file.
• .msg — Microsoft Outlooke-mail message file.
• .oft — Microsoft Outlook e-mail template file.
• .ost — Microsoft Outlook offline e-mail storage file.
• .pst — Microsoft Outlook e-mail storage file.
• .vcf — E-mail contact file.

Executable file extensions

The most common executable file are files ending with the .exe file extension. However, other files can also be run by themselves or with the aid of an interpreter.

Font file extensions

Below are the most common file extensions used with fonts.

• .fnt — Windows font file
• .fon — Generic font file
• .otf — Open type font file
• .ttf — TrueType font file

Image file formats by file extension

There are many different image types and image file extensions that can be used when creating and saving images on the computer. Below is a list of the most common image file extensions.

Internet-related file extensions

The Internet is the most used resource on the computer and because web servers supply the files, there are many different file extensions utilized. Below are a list of the most common file extensions on the web.

Image file extensions, video file extensions, and other extensions listed on this page could also be included with these file extensions mentioned below.

• .asp and .aspx — Active Server Page file
• .cer — Internet security certificate
• .cfm — ColdFusion Markup file
• .cgi or .pl — Perl script file
• .css — Cascading Style Sheet file
• .htm and .html — HTML file
• .js — JavaScript file
• .jsp — Java Server Page file
• .part — Partially downloaded file
• .php — PHP file
• .py — Python file
• .rss — RSS file
• .xhtml — XHTML file

Presentation file formats by file extension

Today, there are a few programs that can create a presentation. Below is a list of the most common file extensions associated with presentation programs.

• .key — Keynote presentation
• .odp — OpenOffice Impress presentation file
• .pps — PowerPoint slide show
• .ppt — PowerPoint presentation
• .pptx — PowerPoint Open XML presentation

Programming files by file extensions

Many file extensions are used for programs before they are compiled or used as scripts. Below is a list of the most common file extensions associated with programming.

Many of the Internet-related file extensions could also be included with these file extensions mentioned below.

• .c — C and C++ source code file
• .cgi and .pl — Perl script file.
• .class — Java class file
• .cpp — C++ source code file
• .cs — Visual C# source code file
• .h — C, C++, and Objective-C header file
• .java — Java Source code file
• .php — PHP script file.
• .py — Python script file.
• .sh — Bash shell script
• .swift — Swift source code file
• .vb — Visual Basic file

There are hundreds of programming languages and the above list is only a small fraction of the most common file extentions.

Spreadsheet file formats by file extension

Below are the most common file extensions used to save spreadsheet files to a computer.

• .ods — OpenOffice Calc spreadsheet file
• .xls — Microsoft Excel file
• .xlsm — Microsoft Excel file with macros
• .xlsx — Microsoft Excel Open XML spreadsheet file

System related file formats and file extensions

Like all other programs, your operating system uses files and has file extensions that are more common than others. Below is a list of the most common file extensions used on operating systems.

The executable file extensions and all other files could also be included in this list.

• .bak — Backup file
• .cab — Windows Cabinet file
• .cfg — Configuration file
• .cpl — Windows Control panel file
• .cur — Windows cursor file
• .dll — DLL file
• .dmp — Dump file
• .drv — Device driver file
• .icns — macOS X icon resource file
• .ico — Icon file
• .ini — Initialization file
• .lnk — Windows shortcut file
• .msi — Windows installer package
• .sys — Windows system file
• .tmp — Temporary file

Video file formats by file extension

Today, several file types are associated with video files to add different types of compression, compatibility, and DRM to video files. Below is a list of the most commonly found video file extensions.

Word processor and text file formats by file extension

Creating text files and using a word processor is one of the most common tasks on a computer. Below is the most common file extensions used with text files and documents.

File Types

This topic explains how to create new file types and how to associate your app with your file type and other well-defined file types. Files with a shared common file name extension (.doc, .html, and so on) are of the same type. For example, if you create a new text editor, then you can use the existing .txt file type. In other cases, you might need to create a new file type.

This topic is organized as follows:

Additional information can be found on the following topics:

Public and Private File Types

Public file types are also known as popular or contentious types because competing applications might want to be associated with these file types. Characteristics of public file types include:

• They are typically defined by standards bodies, and/or are promoted by their defining organizations as interchange formats.
• They are often exchanged between computers and users for diverse purposes.
• They need to be supported on many different platforms.
• Applications from multiple vendors are likely to handle them.

Some examples of file types that are considered public are the image file types .png, .gif, .jpg, and .bmp, and the audio types .wav, .mp3, and .au.

Unlike public file types, private or proprietary file types typically have a format that is implemented and understood by only one application or vendor. As a result, private file types are typically not prone to conflicts between applications. Some file types can start as private file types but later become public file types.

Windows does not differentiate between public and private file types. The distinction is relevant only in making decisions about your choice of file type registration.

Registering a File Type

To associate the file type with an existing application, locate the application ProgID in the registry. To associate the file type with a new application, define a ProgID for your application. For information about defining a new ProgID, see Programmatic Identifiers.

File name extension subkeys have the following general form: extension=ProgID. File name extension subkeys are stored in the HKEY_CLASSES_ROOT subtree.

It is important to include the leading period (.) when creating file type subkeys in the registry. For example, if you want a file type with the short extension .myp and the long extension .myp-file to be opened with an application called MyProgram, use the following syntax:

As demonstrated in the preceding example, if you also register a short file name extension (.myp), you should create a subkey for the long extension (.myp-file) as well. For more information, see File Type Handlers.

Setting Optional Subkeys and File Type Extension Attributes

File type extension entries in the registry have several optional subkeys and attributes.

The file type extension entries that are used by file associations are described in the following table. All values are of the REG_SZ type.

Registry entry	Action
Default	Set the default value of the extension subkey to the ProgID to which it is linked.
Content Type	Set the Content Type value to the file type’s MIME content type.
OpenWithList	Do not use. This subkey contains one or more application subkeys for applications that appear in the Open with dialog box entry for the file type and is intended only for .exe applications on operating systems prior to WindowsВ XP. Use OpenWithProgIds instead.
OpenWithProgIds	This subkey contains a list of alternate ProgIDs for this file type. The programs for these ProgIDs appear in the Open with menu and are available as default Windows Store apps for the file type. Whenever an application takes over this file type by changing the default value, it should also add an entry to this list.
PerceivedType	Set the PerceivedType value to the PerceivedType to which the file belongs, if any. This string is not used by Windows versions prior to WindowsВ Vista. For more information, see Perceived Types and Application Registration.

The general form of a file name extension subkey is as follows. All entry types are of the REG_SZ type.

Important considerations about file types include:

The HKEY_CLASSES_ROOT subtree is a view formed by merging HKEY_CURRENT_USER\Software\Classes and HKEY_LOCAL_MACHINE\Software\Classes

In general, HKEY_CLASSES_ROOT is intended to be read from but not written to. For more information, see the HKEY_CLASSES_ROOT article.

To register a file type globally on a particular computer, create an entry for the file type in the HKEY_LOCAL_MACHINE\Software\Classes subkey.

To make a file type registration visible to the current user only, create an entry for the file type in the HKEY_CURRENT_USER\Software\Classes subkey.

An application can provide its own implementation of a verb, such as open or play, as shown in the following registry example.

Subkeys of the verb subkey include the command line and the drop target method: command and DropTarget.

When you create or change a file association, it is important to notify the system that you have made a change. Do so by calling SHChangeNotify and specifying the SHCNE_ASSOCCHANGED event. If you do not call SHChangeNotify, the change may not be recognized until after the system is rebooted.

To retrieve registry information regarding a file association, use the IQueryAssociations interface. For a scenario that illustrates this procedure, see File Association Sample Scenario.

Both the App Paths and Applications registry subkeys are used to register and control the behavior of the system on behalf of applications. For more detailed information about this functionality, see Application Registration.

Deleting Registry Information During Uninstallation

When uninstalling an application, the ProgIDs and most other registry information associated with that application should be deleted as part of the uninstallation. However, applications that have taken ownership of a file type (by setting the Default value of the file type’s HKEY_CLASSES_ROOT\.extension subkey to the ProgID of the application) should not attempt to remove that value when uninstalling. Leaving the data in place for the Default value avoids the difficulty of determining whether another application has taken ownership of the file type and overwritten the Default value after the original application was installed. Windows respects the Default value only if the ProgID found there is a registered ProgID. If the ProgID is unregistered, it is ignored.

Note that other file-type ownership information is stored in the HKEY_CURRENT_USERsubtree and also is used only when the application that it references is registered. Therefore, this data does not need to be removed when uninstalling an application.

As an example, the following shows the state of the registry before an application is uninstalled:

The following shows the state of those same registry entries after the application has been uninstalled.

File Types That Support Open Metadata

In WindowsВ 7 and later, the following file types support open metadata.