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

FNT file extension

Windows Font File

Font Files

SRT file extension

SubRip Subtitle File

Video Files

SH file extension

Bash Shell Script

Developer Files

GZ file extension

Gnu Zipped Archive

Compressed Files

EPUB file extension

Open eBook File

eBook Files

7Z file extension

7-Zip Compressed File

Compressed Files

ICNS file extension

Mac OS X Icon Resource File

System Files

PDF file extension

Portable Document Format File

Layout Files

TMP file extension

Temporary File

Backup Files

GBR file extension

Gerber File

Data Files

RSS file extension

Rich Site Summary

Web Files

BMP file extension

Bitmap Image File

Raster Image Files

ODT file extension

OpenDocument Text Document

Text Files

PS file extension

PostScript File

Vector Image Files

TEX file extension

LaTeX Source Document

Text Files