Winmail.dat Opener

Received a winmail.dat attachment you can't open? Drop it here to read the email inside and extract the real attachments — free, online, and without installing Outlook.

Drop your file here

Accepts winmail.dat files (TNEF) from Outlook · Max ~100 MB

Choose file — open the live tool

Processed 100% in your browser — your file is never uploaded.

About this Winmail.dat Opener tool

A winmail.dat file appears when someone sends you email from Microsoft Outlook with Rich Text formatting switched on. Outlook wraps the message body and every attachment in a proprietary container called TNEF (Transport Neutral Encapsulation Format) and names it winmail.dat. If you don't use Outlook — or even if you do, with the wrong settings — all you see is an useless .dat file instead of the invoice, document or photo that was actually sent.

This opener decodes the TNEF container in your browser. It recovers the message text and pulls out every embedded attachment with its original filename, ready to download. Nothing is uploaded to a server, which matters: winmail.dat files usually contain real business email.

How to use it

Save the winmail.dat attachment from your email to your device.
Drop it onto this page (or tap “Choose file”) and press Convert.
Read the recovered email in the preview and download any attachments that were hidden inside.

Frequently asked questions

Why did I receive a winmail.dat file?

The sender's Outlook is configured to send mail in Rich Text Format. Outlook packs the formatted message and attachments into winmail.dat, which most other email apps can't decode. Asking the sender to switch to HTML or Plain Text format prevents it.

Is it safe to open winmail.dat online here?

Yes. The file is decoded locally in your browser and never uploaded, so the email and its attachments stay on your device.

The opener found no attachments — why?

Some winmail.dat files contain only the formatted message body and no attachments. In that case the recovered message text is what the sender actually packaged.

Can I open winmail.dat on my phone?

Yes — this tool works in mobile browsers on Android and iPhone, no app install needed.