File extensions – definition and basic information


File extensions are the integral parts of the files that are on each computer. Often, when working on a computer, we encounter a wide range of files, such as docx, ppt, part, mp3 or rmvb. We realize that they are there – but we often do not know what they are for on our computer.

File extension, also known as the filename extension is a suffix added to the name of a computer file, usually consisting of a number of characters placed after the last dot in the filename, which gives us information about its coding. In other words a file extension is a file format. It allows the operating system (e.g. Windows) to recognize what program it should try to open the file.

In the table below you will find a random selection of popular file extensions.


File extension The full name of the file Category

COM file extension

DOS Command File

Executable Files

CSV file extension

Comma Separated Values File

Data Files

CUR file extension

Windows Cursor

System Files

HQX file extension

BinHex 4.0 Encoded File

Encoded Files

MAX file extension

3ds Max Scene File

3D Image Files

PDB file extension

Program Database

Database Files

PDF file extension

Portable Document Format File

Layout Files

RA file extension

Real Audio File

Audio Files

SVG file extension

Scalable Vector Graphics File

Vector Image Files

TMP file extension

Temporary File

Backup Files

TORRENT file extension

BitTorrent File

Misc Files

TXT file extension

Plain Text File

Text Files

WMV file extension

Windows Media Video File

Video Files

XLR file extension

Works Spreadsheet

Spreadsheet Files

XLSX file extension

Microsoft Excel Open XML Spreadsheet

Spreadsheet Files