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

CSR file extension

Certificate Signing Request File

Web Files

DAT file extension

Data File

Data Files

FLV file extension

Flash Video File

Video Files

GED file extension

GEDCOM Genealogy Data File

Data Files

GPX file extension

GPS Exchange File

GIS Files

GZ file extension

Gnu Zipped Archive

Compressed Files

ICO file extension

Icon File

System Files

IFF file extension

Interchange File Format

Audio Files

LNK file extension

Windows File Shortcut

System Files

LUA file extension

Lua Source File

Developer Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

TAX2012 file extension

TurboTax 2012 Tax Return

Data Files

TMP file extension

Temporary File

Backup Files

XLR file extension

Works Spreadsheet

Spreadsheet Files

YUV file extension

YUV Encoded Image File

Raster Image Files