What is EML File Extension? Query Resolved Here!

Jamie Kaler ~ March 17, 2025 ~ 5 Minutes Reading

Define EML File formats:

  • EML File Developer: Microsoft
  • File Type: Electronic Mail
  • MIME Type: Message/RFC 822
  • File Format of EML: Text & Binary

What is EML File Format?

EML file is an electronic Mail file consisting of email messages along with attachments. This is an individual email message having a .eml extension that archives email messages that aim at preserving original headers and formatting. The file consisted of plain ASCII text which is for headers, then the main message body, followed by hyperlinks, and lastly attachments. The header needs to have the email address of the sender, the subject line text, as well as time. In the technical language, The file consisted of an email file which is referred to as the RFC-822 file format.

Structure of EML File format

  1. Header: It contains metadata such as sender, cc, bcc, date, subject, timestamp and MIME Version.
  2. Body: It contains messages in a plain text file that follows RFC 822.
  3. Attachments: File embedded with email are encoded using MIME(Base 84 Encoding) and are included within the EML file format.

Here is the header view of an EML format. It usually looks like the below image but if there is any change then either it is not and your EML files extension is corrupt.

what is eml file

Technical Standard and Compatibility:

  1. RFC-822 and RFC-2822: EML file usually follows RFC 822 but now it’s updated as RFC-2822 standard for storing email messages.
  2. MIME Support: As EML Format uses MIME(Multipurpose Internet Mail Extensions), they contain images, formatted Text, and attachments.
  3. UNICODE Compatibility: EML file supports different character sets for multi-language compatibility.

Email clients supporting EML file format: This is supportive of emailing clients such as Windows Live Mail, Outlook Express, Thunderbird, Entourage, PocoMail, and lots more.

How to Access EML Files?

In the situation where the user has a file supporting emailing client then simply double click on it to open But, suppose, somehow you failed to access the format in Outlook Express then below mentioned steps help further:

  • Begin the process by opening ‘My Computer
  • Then press ‘Tools’>> ‘Folder’ Options
  • Then click the ‘File Types’ Tab and choose ‘Outlook Express email’
  • Click the ‘Advanced’ tab
  • In new windows, choose Open and press Edit
  • Then in the application used for performing the action box, ensure for typing the command C:\Program Files\Outlook Express\MSIMN.EXE” /eml:%1 and click ‘OK’ in the two other windows.

How to Create EML File?

The file generates in so many emailing applications. Most email clients create it automatically. To open the EML file on desktop, just drag and drop the email messages available in the file supportive of email clients like Entourage, Thunderbird, Outlook Express, etc. or you also open or read it using Notepad.

How to Open EML File Extension?

  1. Double Click: Right-click on the EML file, click on Open With, and select an email client (if a supported email client is already installed).
  2. Drag and Drop: Navigate to EML extension, hold cursor on the EML and drop into the email application such as Outlook or Thunderbird.
  3. Open with Text Editor: Use Notepad++, VS Code to open raw data of EML format.

Use Cases of EML Files:

  1. Email Backup and Archiving: It allows you store individual email message with maintained their original formatting, metadata and attachments. Used by individual and professional users to preserve important communication for long term preservation.
  2. For Legal Investigations: EML file maintains email headers, including timestamp, and sender/recipients details and EML files are admissible in corut5, treated as documentary evidence, but their reliability will be subjected to investigation with proper authentication and accessibility.

What are EML files & Difference between EML And EMLX Files?

The files are created via Windows-based emailing applications like Entourage, Outlook, etc. On the other hand, EMLX files are generated from Macintosh-based email clients such as Apple Mail and lots of others.

How to Convert EML Files?

If you have stored batch Email files on your local drive or want to export EML format into other file extension then we recommend you to opt Jagware EML Converter as it allows users to export EML extension into 35+ saving formats such as PST, MSG, TXT, MBOX and many more popular extensions. It’s a completely tried and tested utility to convert 20000 EML files at once and it offers fully maintained metadata without losing any original structure. To use this, you just go on the download button and easily use it on your machine.

Summary

In this guide, we have introduced about what is EML file, its structure, compatibility, and technical standards. We have also explained how EML files contain individual emails along with attachments with preserving original formatting and email headers. Additionally, we have shared ways to open EML files using email clients and text editors. In additon, We have also explained use cases of EML files, such as email backup and archiving, to know the crucial role of EML file in legal investigations.