Windows file names have two parts separated by a period: first, the file name, and second, a three- or four-character extension that defines the file type. In expenses.xlsx, for example, the first part of the file name is expenses and the extension is xlsx.
Extensions tell your computer which application created or can open the file and which icon to use for the file. For example, the docx extension tells your computer that Microsoft Word can open the file and to display a Word icon when you view it in File Explorer.
Most file name extensions are compatible with more than one program that you have installed. You can change a file name extension, but that won't convert the file to another format or change anything else about it except the file name. To learn more about how to change which program will open a file, read Change default programs in Windows 10.
If you don’t see file name extensions when you view files in File Explorer:
-
In the search box on the taskbar, type file explorer, and in the search results, select File Explorer.
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In File Explorer under View, in the Show/hide group, select the File name extensions check box.
Below is a list of common Windows file name extensions and formats.
|
Extension |
Format |
|---|---|
|
aac, adt, adts |
Windows audio file |
|
accdb |
Microsoft Access database file |
|
accde |
Microsoft Access execute-only file |
|
accdr |
Microsoft Access runtime database |
|
accdt |
Microsoft Access database template |
|
aif, aifc, aiff |
Audio Interchange File format file |
|
aspx |
ASP.NET Active Server page |
|
avi |
Audio Video Interleave movie or sound file |
|
bat |
PC batch file |
|
bin |
Binary compressed file |
|
bmp |
Bitmap file |
|
cab |
Windows Cabinet file |
|
cda |
CD Audio Track |
|
csv |
Comma-separated values file |
|
dif |
Spreadsheet data interchange format file |
|
dll |
Dynamic Link Library file |
|
doc |
Microsoft Word document before Word 2007 |
|
docm |
Microsoft Word macro-enabled document |
|
docx |
Microsoft Word document |
|
dot |
Microsoft Word template before Word 2007 |
|
dotx |
Microsoft Word template |
|
eml |
Email file created by Outlook Express, Windows Live Mail, and other programs |
|
eps |
Encapsulated Postscript file |
|
exe |
Executable program file |
|
flv |
Flash-compatible video file |
|
gif |
Graphical Interchange Format file |
|
htm, html |
Hypertext markup language page |
|
ini |
Windows initialization configuration file |
|
iso |
ISO-9660 disc image |
|
jar |
Java architecture file |
|
jpg, jpeg |
Joint Photographic Experts Group photo file |
|
m4a |
MPEG-4 audio file |
|
mdb |
Microsoft Access database before Access 2007 |
|
mid, midi |
Musical Instrument Digital Interface file |
|
mov |
Apple QuickTime movie file |
|
mp3 |
MPEG layer 3 audio file |
|
mp4 |
MPEG 4 video |
|
mp4 |
MPEG 4 video |
|
mpeg |
Moving Picture Experts Group movie file |
|
mpg |
MPEG 1 system stream |
|
msi |
Microsoft installer file |
|
mui |
Multilingual User Interface file |
|
|
Portable Document Format file |
|
png |
Portable Network Graphics file |
|
pot |
Microsoft PowerPoint template before PowerPoint 2007 |
|
potm |
Microsoft PowerPoint macro-enabled template |
|
potx |
Microsoft PowerPoint template |
|
ppam |
Microsoft PowerPoint add-in |
|
pps |
Microsoft PowerPoint slideshow before PowerPoint 2007 |
|
ppsm |
Microsoft PowerPoint macro-enabled slideshow |
|
ppsx |
Microsoft PowerPoint slideshow |
|
ppt |
Microsoft PowerPoint format before PowerPoint 2007 |
|
pptm |
Microsoft PowerPoint macro-enabled presentation |
|
pptx |
Microsoft PowerPoint presentation |
|
psd |
Adobe Photoshop file |
|
pst |
Outlook data store |
|
pub |
Microsoft Publisher file |
|
rar |
Roshal Archive compressed file |
|
rtf |
Rich Text Format file |
|
sldm |
Microsoft PowerPoint macro-enabled slide |
|
sldx |
Microsoft PowerPoint slide |
|
swf |
Shockwave Flash file |
|
sys |
Microsoft DOS and Windows system settings and variables file |
|
tif, tiff |
Tagged Image Format file |
|
tmp |
Temporary data file |
|
txt |
Unformatted text file |
|
vob |
Video object file |
|
vsd |
Microsoft Visio drawing before Visio 2013 |
|
vsdm |
Microsoft Visio macro-enabled drawing |
|
vsdx |
Microsoft Visio drawing file |
|
vss |
Microsoft Visio stencil before Visio 2013 |
|
vssm |
Microsoft Visio macro-enabled stencil |
|
vst |
Microsoft Visio template before Visio 2013 |
|
vstm |
Microsoft Visio macro-enabled template |
|
vstx |
Microsoft Visio template |
|
wav |
Wave audio file |
|
wbk |
Microsoft Word backup document |
|
wks |
Microsoft Works file |
|
wma |
Windows Media Audio file |
|
wmd |
Windows Media Download file |
|
wmv |
Windows Media Video file |
|
wmz, wms |
Windows Media skins file |
|
wpd, wp5 |
WordPerfect document |
|
xla |
Microsoft Excel add-in or macro file |
|
xlam |
Microsoft Excel add-in after Excel 2007 |
|
xll |
Microsoft Excel DLL-based add-in |
|
xlm |
Microsoft Excel macro before Excel 2007 |
|
xls |
Microsoft Excel workbook before Excel 2007 |
|
xlsm |
Microsoft Excel macro-enabled workbook after Excel 2007 |
|
xlsx |
Microsoft Excel workbook after Excel 2007 |
|
xlt |
Microsoft Excel template before Excel 2007 |
|
xltm |
Microsoft Excel macro-enabled template after Excel 2007 |
|
xltx |
Microsoft Excel template after Excel 2007 |
|
xps |
XML-based document |
|
zip |
Compressed file |
