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

3DM file extension

Rhino 3D Model

3D Image Files

LOG file extension

Log File

Text Files

MDB file extension

Microsoft Access Database

Database Files

FNT file extension

Windows Font File

Font Files

RM file extension

Real Media File

Video Files

ICNS file extension

Mac OS X Icon Resource File

System Files

PART file extension

Partially Downloaded File

Misc Files

TIFF file extension

Tagged Image File Format

Raster Image Files

XLR file extension

Works Spreadsheet

Spreadsheet Files

GADGET file extension

Windows Gadget

Executable Files

7Z file extension

7-Zip Compressed File

Compressed Files

ICO file extension

Icon File

System Files

RA file extension

Real Audio File

Audio Files

OBJ file extension

Wavefront 3D Object File

3D Image Files

PY file extension

Python Script

Developer Files