What is an EML file?
An EML file is a single email message saved as a plain-text file in the RFC 822 format, with the headers, the body and any attachments inside. Below: who produces EML files, how they are built, how to open and save them, and how to turn one into a PDF. You can also drop one into SaveMail and read it in your browser; nothing is uploaded.
EML file: definition and where it comes from
An EML file (extension .eml) is one email message stored as text, exactly as a mail server would transmit it. It holds the headers (From, To, Date, Subject, Message-ID), the message body in plain text or HTML, and every attachment encoded inside the same file.
Many programs produce this format. Gmail creates one when you open a message, click the three dots and choose Download message. Apple Mail, Thunderbird, Windows Mail and most desktop clients save messages as EML through File, Save As, or by dragging a message to the desktop (Apple Mail uses the closely related .emlx variant). Mail servers, ticketing systems and archiving tools also export EML because it is the most portable email format there is.
Outlook is the exception: it saves messages as MSG files by default, although it can open an EML you receive.
Have the email as a file (EML, MSG, MBOX)? Convert it to PDF in your browser: nothing is uploaded.
How an EML file is structured
Open the file in a text editor and you will see two parts. The first is a block of headers, one per line, defined by the RFC 822 standard (updated as RFC 5322): who sent the message, who received it, when, the subject, and a unique Message-ID. Those headers matter for records, because the Message-ID lets you show that this is the same message that sits in the sender's mailbox.
The second part is the body, organized by the MIME standard. A MIME message is split into parts separated by a boundary string: one part for the plain-text body, one for the HTML version, and one part per attachment or inline image. Binary attachments are encoded as Base64 text, which is why the file is bigger than the attachments it contains, by roughly a third.
Because everything is text, the message file can be read by any program that understands MIME, and it survives being copied between Windows, macOS, Linux and phones without conversion.
How to open an EML file
You do not need Outlook. The quickest route is a browser:
- Go to the EML to PDF converter or the SaveMail home page.
- Drop the file onto the page or choose it with the file picker.
- The message appears with its headers, body, inline images and a list of attachments you can download one by one or as a ZIP.
The file is parsed by JavaScript in your tab; there is no upload endpoint, so the email never leaves your device. Other ways to open one: double-click it on a Mac (Apple Mail) or on Windows (Windows Mail or Outlook), or drag it into Thunderbird. Gmail cannot open one from your computer, but if an EML arrives as an attachment, Gmail shows it as a nested message; see how to open an EML file in Gmail. Every option by platform is in how to open an EML file.
How to save an email as an EML file
- Gmail: open the message, click the three dots in the message header and choose Download message. Gmail downloads an
.emlfile named after the subject. - Apple Mail: select the message, then File, Save As, and pick Raw Message Source; or drag the message to the desktop.
- Thunderbird: right-click the message and choose Save As; the result is an EML.
- Outlook for Windows: dragging a message to the desktop gives a
.msgfile, not EML. Outlook on the web has a Download option in the message menu that saves an.emlfile.
Downloading messages one at a time is fine for a handful. For a whole mailbox see how to download emails from Gmail; the mailbox-wide export there is MBOX, not EML.
How to convert an EML file to PDF, and the limits
Drop the file into SaveMail and press Save as PDF. Your browser's print dialog opens; choose Save as PDF as the destination, and the page size and margins come from that dialog. The text in the PDF stays selectable and searchable because the message is rendered as a page, not photographed. A compact mode hides quoted replies and signatures for a shorter PDF.
What a PDF cannot carry: attachments stay separate files. Download them from the attachment list (one by one or as a ZIP) and keep them next to the PDF. Encrypted messages (S/MIME, PGP) are shown as encrypted, not decrypted. One message is rendered at a time, so combining many messages into one merged PDF is not something the converter does today; convert them one after another. SaveMail also does not edit the email or convert a PDF back to EML.
Size: the file is usually a few KB to a few MB. The practical limit in the browser is memory, so even messages with large attachments open, only more slowly.
EML vs MSG vs MBOX vs PST
| Format | What it holds | Produced by | Opens in a browser with SaveMail |
|---|---|---|---|
| EML | One message, plain text, RFC 822 headers plus MIME parts | Gmail, Apple Mail, Thunderbird, most clients and servers | Yes |
| MSG | One message, binary OLE compound file | Outlook for Windows | Yes |
| MBOX | Many messages concatenated in one text file | Google Takeout, Thunderbird, Apple Mail export | Yes; each message is listed and opened one at a time |
| PST | Whole mailbox: folders, mail, contacts, calendar | Outlook export or archive | No; open it in Outlook and save messages as MSG first |
If you mostly receive single messages, EML is the format you will meet most often, and it is the easiest one to read, convert and keep.
Frequently asked questions
What program opens an EML file?
Any mail client: Apple Mail, Thunderbird, Windows Mail, Outlook. Without a client, drop the file into SaveMail and it opens in your browser with its attachments; nothing is uploaded.
How do I save an email as an EML file?
In Gmail open the message, click the three dots and choose Download message. In Apple Mail or Thunderbird use Save As. Outlook for Windows saves MSG instead; Outlook on the web's Download option gives an EML.
How do I download an EML file?
From Gmail: three dots, Download message. From a link or an attachment: save it like any file. Then open it in a mail client or drop it into SaveMail.
Can EML files be malicious?
The EML itself is text and cannot run, but the attachments inside can be anything and an HTML body can link to a phishing page. SaveMail sanitizes the HTML before display and lists attachments without running them; treat those attachments like any download from that sender.
Can I open an EML file on an iPhone?
Yes. Tapping an EML attachment in the Mail app opens it as a message. You can also open SaveMail in Safari, pick the file from Files, and save it as PDF through the share or print sheet.
How do I combine or merge EML files?
SaveMail renders one message at a time and does not merge EML files. To keep a set together, convert each one to PDF into the same folder, or import the EML files into a mail client such as Thunderbird and export the folder as an MBOX.