A .eml file is a single email message saved as a text file on your computer

When you see a file ending in .eml, you are looking at one email — the message itself, plus its subject line, sender, recipient, and date. Your email program created it, usually without you asking. Unlike the inbox inside Outlook or Gmail, which holds dozens or hundreds of messages in one database, a .eml file is a standalone copy of one message that your computer treats like any other document.

The letters stand for Electronic Mail. The format is a standard that almost every email program understands, so you can open a .eml file in Outlook, Thunderbird, Apple Mail, or even a text editor. This makes .eml files useful when you need to move an email from one program to another, save it for a record, or send it to someone else as a file rather than forwarding it through email.

Key Takeaways

  • A .eml file is one email message saved as a separate file on your computer, not stored inside an email program's database.
  • Your email program may create .eml files automatically when you read messages, or you can manually save a message as a .eml file yourself.
  • You can open a .eml file in almost any email program or even in a text editor, because the format is a standard that all programs recognize.
  • Common reasons to work with .eml files are moving emails between programs, keeping a backup copy, or sharing a message with someone as a file.

Why your email program created .eml files

If you recently switched email programs or imported messages from an old account, your new program may have converted those messages to .eml files during the transfer. This happens because different email programs store messages in different ways — Outlook uses a format called PST, Gmail stores everything on Google's servers, and Thunderbird uses its own system. When you move messages between them, the program often saves each one as a .eml file as an intermediate step, then imports them into its own format.

You may also have created .eml files yourself without realizing it. In Outlook, right-clicking a message and choosing "Save As" creates a .eml file. In Thunderbird, dragging a message to your desktop does the same thing. In Gmail, you cannot save as .eml directly, but third-party tools can read your messages in that format. If you see a folder full of .eml files on your computer, it usually means you (or a program acting on your behalf) saved messages there intentionally at some point.

How to open a .eml file

The simplest way is to double-click the file. Your computer will open it in whatever email program you have set as the default — usually Outlook, Thunderbird, or Apple Mail. The message will display exactly as it appeared in your inbox, with the subject line, sender, date, and body text all visible.

If you do not have an email program installed, or you want to read the file without opening your email software, you can open a .eml file in any text editor. Right-click the file, choose "Open With," and select Notepad (on Windows) or TextEdit (on Mac). You will see the raw code underneath the message — headers that show routing information, the sender's address, the date the message was sent, and then the body text. This is harder to read than opening it in an email program, but it works if you just need to check what is in the file.

Moving .eml files between email programs

If you have a folder of .eml files and want to import them into a new email program, most programs have an import function that handles this. In Outlook, go to File > Open & Export > Import/Export, then choose "Import from another program or file" and select the folder containing your .eml files. Thunderbird has a similar import tool under Tools > Import. The program will read each .eml file and add the messages to your inbox.

You can also drag .eml files directly into some email programs. In Thunderbird, dragging a .eml file into a folder usually imports it. In Outlook, this does not always work reliably, so using the import function is safer. If you are moving a large number of messages, importing is faster than opening each file individually.

When .eml files are useful

Keeping a .eml file of an important message — a receipt, a contract, a confirmation from a service — gives you a backup that does not depend on your email account staying active. If your email account is deleted or hacked, the .eml file on your computer is still there. You can also share a .eml file with someone else by attaching it to an email or sending it through a file-sharing service, which is sometimes clearer than forwarding a message (the recipient sees exactly what you received, not a chain of replies).

.eml files are also useful if you need to move your entire email history from one program to another. Exporting your messages as .eml files and then importing them into the new program preserves the original message, date, and sender information. This is more reliable than copying and pasting message text, which loses formatting and metadata.

Cleaning up .eml files you do not need

If you have a folder full of .eml files left over from an old email migration or import, and you have already moved those messages into your current email program, you can delete the .eml files safely. They are just copies — deleting them does not affect the messages in your inbox. You can select all the files in the folder and press Delete, or drag them to the Recycle Bin (on Windows) or Trash (on Mac).

Before you delete a large batch of .eml files, check that the messages are actually in your current email program. Open your inbox and search for a subject line or sender name from one of the files to confirm the message is there. Once you are sure, the .eml files are safe to remove.

Frequently Asked Questions

Can I open a .eml file without an email program?

Yes. Right-click the file, choose "Open With," and select Notepad (Windows) or TextEdit (Mac). You will see the message text mixed with technical headers, but you can read the content. For a cleaner view, use an online .eml viewer by uploading the file to a website that displays .eml files — no installation needed.

Is a .eml file the same as a .msg file?

No. A .msg file is Outlook's own format and contains more information than a .eml file, including formatting and attachments stored in a proprietary way. A .eml file is a standard format that all email programs recognize. If you have a .msg file, you can open it in Outlook, but other programs may not read it correctly.

What happens if I delete a .eml file?

The message is gone from that file, but if the message is also in your email inbox, nothing changes — you still have it there. If the .eml file was your only copy of the message, it is permanently deleted. Always check that a message exists in your email program before deleting the .eml file.

Can I edit a .eml file and send it again?

You can edit the text in a .eml file using a text editor, but this is not recommended. Changing the file may break the formatting or headers, and the message will not send properly if you try to open it in an email program afterward. If you need to modify a message, open it in your email program, copy the text, and create a new message instead.