• Maximum 80 Characters
  • Most important words should appear in the first 5-7 words
  • HTML not allowed in the subject line


  • Format: HTML
  • Maximum file size: 150KB (html + images)
  • Recommended width: 500 – 700 pixels
  • Recommended height: 500 – 1000 pixels
  • Use inline-CSS only
  • All the content must reside BETWEEN <body> and </body>

o    Some email clients purge everything outside of <body> tag, including the attributes defined in <body> tag.

  • Image formats allowed: GIF or JPEG only
  • All the graphics used must be 72dpi
  • Text: Maximum 300 words


  • Background images
  • Nested background colors
  • Flash, or other plugins
  • Javascript
  • Animated GIF
  • BMP, TIFF, and any other formats besides PNG, GIF or JPEG
  • <object>, <embed>, <form>, <style>, <script> tags
  • CSS floats, CSS positioning
  • Web Fonts as HTML, use default System fonts


  • Instead of using cellpadding to create margins, use <div style=”margin:5px”>.
  • All the hex numbers for colors must start with #.
  • Defined alt attribute in all the main images.
  • Include the most important message at the top of the email.
  • Use text instead of graphic for your tagline or important message.
  • The email should make sense even without the graphics for those recipient who block images by default.
  • Avoid thick borders, spam-like words, and excessively large fonts

There really isn’t a standard for HTML email. What appears fine in one email client doesn’t look right in another. This makes it almost impossible to create a dynamic HTML email that will display well in every email client application.
The guideline provided above will help ensure your mailing will appear as intended ( or close to it ) on major email clients such as MS Outlook 2003, MS Outlook 2007, Hotmail, Live Mail, Yahoo! Mail, Gmail, and AOL.

Different email clients have different limitations and restrictions. To list a few –

  • Outlook 2007 does not support:

o    Animated GIF, background images, nested background colors

o    CSS floats, CSS positioning

  • Yahoo! Mail and Gmail:

o    Renders only the content between <body> tags

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