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How Many Types of Email Attachments Are There in 2023? Which Are The Dangerous Ones?

Written by, Sandeep Kumar

Updated March, 14, 2023

We’re sure you’re well aware that emails are the most widely spread type of communication worldwide. Additionally, they also have the ability to send attached files.

Though emails have a built-in restriction for larger files (more than 20 or 25MB), they’re still vastly used for sending all sorts of files.

But which files can you attach?

Read on and find out how many types of email attachments are there and which ones to keep an eye out for.

What Kind Of Files Can Be Attached to an Email?

We’re all fans of the paperclip button in emails, right? And most of us know how to use it.

But, let’s discover all the possible file formats that we can actually use with this extremely beneficiary button to send through.

1. Documents

Documents are the most frequent attachments and files delivered by email as a communication tool, particularly as an official and business communication channel.

Here are all the supported document formats to send through an email:

2. Images

Images like CV photos, ad banners, updated menus from a graphic designer, GIFs, etc., contain plenty of information.

So, here are the file formats that are supported in an email attachment:

3. Media files

Media files or audiovisual content can also be shared through email attachments. Of course, each email provider has different rules regarding the maximum size of this content – since they’re the largest ones to be sent as attachments.

For example, Outlook offers 20MB, but others offer far less. Still, Gmail with up to 25MB is the absolute leader in the permitted size of files attached.

Video file formats

Audio file formats

The name itself reveals everything – a compressed file is a file that has been reduced in size, typically by removing unnecessary data or using a more efficient compression algorithm.

Compressed files, thus, take up less space and can easily be downloaded, making them ideal for file transfers and attachments.

There are various compression algorithms, and each one can produce a different type of compressed file.

The most common compression formats are:

Which Email Attachments Are Generally Safe To Open?

We’ve decided to break it down into three tables that elaborate on all the possible email attachment types one can get to answer this question. Furthermore, we divided them into three categories: threatening, generally safe, and highly hazardous.

Safe Attachments Formats

Format – ending letters Description Status – SAFE
.au Audio, basic Common
.avi video Common
.bmp Bit-map/ image Common
.cda Audio – CD format Common
.cdr Corel draw/ data Common
.chf Remote control configuration Not common
.drw CAD/ drawing file Common
.dwg CAD/ Adobe Illustrator Common
.dxf Universal data exchange format/ CAD Common
.eps Post script/  image Common
.gif Internet image Common
.gwf PCAnywhere/ Gateway file Not common
.hlp Help file Not common
.ht Hyperterminal setting file Not common
.ico Icon file Common
.img Image file Common
.iso CD recordable image Not common
.jpeg / .jpg Internet image file Common
.ldb MS access/ lock file Not common
.log Log file, generic Common
.mdb MS Access file Common
.mde MS access file/ unchangeable design Common
.mdw Workgroup security file Not common
.mid / .midi Audio MIDI file Common
.mov Movie – quicktime format Common
.movie Sgi format Common
.mp1 / .mp2 / .mp3 Audio mpeg format Common
.mpeg / .mpg Video MS format Common
.msg Message file Common
.nws Microsoft Internet News message Common
.obd MS Office Binder Common
.pcl Output to HP printer Not common
.pcx Black and white fax image Not common
.pdd Photo Deluxe format Common
.pdf Acrobat Reader document Common
.pic Image Common
.pps MS powerpoint slide show Common
.pub MS publisher data file Common
.qbb Intuit quick books backup file Common
.qbw Intuit quick books work file Common
.qdb Intuit quicken data file Common
.ra RealPlayer audio info Common
.snd Audio Common
.text Plain text Common
.tga Image Common
.tif Image Common
.tsv Tab-separated values Common
.txt Plain text Common
.wav Audio Common
.wma Audio Common
.wmf MS windows metafile Common
.wri Document MS write Common
.xlt MS Excel template Common

Pottentially Hazardous Attachments Formats

Format – ending letters Description Status – Caution / Low risk
.alx HTML layout Low risk
.asp Active server (web) page (definition) May contain unwanted programming – Low risk
.cab Compressed file storage Caution – may contain infected files
.cur Cursor (pointer) definition Common, Low risk
.dic Dictionary Caution – Low risk
.doc Microsoft Word file May contain threats
.dot MS Word Template – New document starting Low risk
.fav Outlook Navigator bar file Could activate a local program
.grp Windows program manager file Could activate a local program
.gtar Compressed file storage Low risk – May contain infected files
.gz Compressed file storage Low risk – May contain infected files
.htm / .html Web page Hypertext file Low risk
.inf Installation information file Local settings could be altered
.ini Initialization settings info Local settings could be altered
.lnk Short definition link Could activate a local program
.msi MS installer package info Local settings could be altered
.msp MS installer patch info Local settings could be altered
.oft MS outlook template Low risk
.pbk Phonebook, Dial up networking Local settings could be altered
.pot MS PowerPoint template May contain infected programming
.ppt MS PowerPoint data file Nasty programming
.shtml Security hypertext mark up file Low risk
.sys System information file Local settings could be altered
.tar / .tgz UNIX compressed file storage May contain infected files
.ttf True type font Local settings could be altered
.url Internet shortcut Local settings altered
.uu Internet transfer format for all files (UUEncode) May contain infected files
.vir Norton AV definition file Local settings altered
.wb2 Spreadsheet Nasty programming
.wbk MS Word/ Backup file Nasty programming
.wiz MS Word/ Wizard definition Nasty programming
.wk4 Spreadsheet Lotus(123) Nasty programming
.wks MS Excel worksheet Nasty programming
.wpd Word Perfect document Nasty programming
.xlk MS Excel/ Backup file Nasty programming
.xls MS Excel/ Spreadsheet book Nasty programming
.xml Extended markup language Could activate a local program
.z / .zip Compressed UNIX file storage Possibility of Infested files


Dangerous Attachments Formats

Format – ending letters Description Status – Caution / Dangerous
.bas Script, (Basic) programming language Common
.bat DOS batch file Common
.bin Octet-stream, Application Not common
.c C++ language programming Not common
.cmd Advanced batch (script) file Common
.com Older DOS/ Program Common
.cpl Control panel application Not common
.dll Dynamic link library (program helper file) Common
.eml Microsoft Internet Mail Common
.exe Program, executable Common
.java Internet universal scripting Not common
.js / .jse Programming (java) script Not common
.pif Program start info file Common
.pl PERL programming Not common
.reg Windows import/export registry Common
.scr Screen saver file Common
.sct Scriptlet file (programming) Not common
.vbe / .vbs Visual Basic Scripting Common
.wsc Scriptlet file Common
.wsf Script Not common
.wsh Windows scripting programming Common



While you certainly can’t attach an entire movie in your email, a short link leading to the movie will deliver the message, i.e., as if you sent the entire movie.

However, hackers are aware that people send all sorts of stuff via their personal (and business) emails; hence, the reason why they try to hack into emails through these files. Or impersonate some of these files for disguising phishing links and other bedazzlement scams.

So, whenever you feel at threat – make sure to return to this article and the thorough list of email attachment files to keep an eye on.

Keep it smart, keep it safe, keep it simple — and always come back to us for some more hacks for your ultimate online security!