What Are Email Headers and How Can I View Them?

An email consists of the email headers and the email message (body). The email headers provide you with information about the transmission of an email, from which you can obtain the following information:

  • The Sender
  • The Recipient

  • The Date

  • The Subject

  • The Servers involved in the transmission from sender to recipient

Since almost all email programs hide the emails headers by default, the following examples explain how to view the email headers in various email programs and Webmail.

Viewing Headers in Email Programs

  • Thunderbird (and other Mozilla clients)
    Open the email, click the More button on the right, and then select View Source from the menu.
  • Outlook 365 and 2010/2013/2016
    Double-click the email and click File > Properties from the menu. The headers will be displayed in the Internet Headers area.
  • Windows Mail
    Right-click the message and select Properties. Now click on the Details tab, where all header information is displayed.
  • Apple Mail (on the Mac)
    Open the email and press Shift + cmd + H on the keyboard simultaneously (⇧ + ⌘ + H).
  • Opera
    Open the email and right-click on the message text. Click View All Headers and Message.

View Headers in Webmail

  • Gmail
    Open the email and click the More button (three vertical dots next to the date and the reply button). Click Show original. This will open another window with all header information at the top (under the "Download Original" link).
  • WebMail
    Open the email and click on the button with three horizontal lines. Click Display source.
  • Yahoo! mail
    Open the email, click the More button (three horizontal dots at the top of the message window), and then click View raw message. The complete headers are now displayed in a new window.
  • AOL Webmail
    When the email is open, click on the Details button at the top. The email headers are then displayed in a new window.
  • Outlook Web App (new version)
    Open the email and click the down arrow button at the top right. Select the option Show message source.
  • Outlook Web App (old version)
    Open the email and click on the symbol with the three dots [...] in the upper right corner. Select the option Show message details.