How to Mimic Underlining in a Plain-Text Email

Not as Pretty as Html, but Easy

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Most emails these days are HTML-based. In HTML, the text is encoded to handle formatting such as bolding, italicizing, coloring, positioning, and layout. In contrast, a plain-text email looks like the sender typed in on a typewriter: no formatting, no images, no pretty fonts, and no hyperlinks. It’s often displayed using a mono-spaced font in which each character takes up the same amount of space on the line as every other.

Why Use Plain-Text Emails?

Sometimes, sending a plain-text email is more appropriate than sending an HTML message — for instance, when you want to be sure that the recipient's email app won't render fancy HTML erroneously or unattractively. In fact, while they are not nearly as attractive as HTML-based emails, plain-text emails play a significant role in a well-rounded email marketing strategy, because plain-text email generally has a higher open and click rate than HTML email.

While the plain text may be plain, it's almost universally readable by devices that receive email, from phones and tablets to computers of all platforms.

HTML, Plain Text, and MIME

Most emails are sent via SMTP in MIME (multipurpose internet mail extensions) format, which means that a plain-text version of your email is bundled along with the HTML version. Unless you’re sending out a solely plain-text email, multipart MIME should be part of every email campaign because spam filters like finding a plain-text alternative, and some people prefer it.

How to Mimic Underlining in Plain-Text Email Messages

Using plain-text email has limitations, though: You can't easily add formatting elements that add emphasis, such as underlining. Still, you can mimic an underline effect while retaining the reliable legibility you're after.

To indicate underlining in a plain-text email, use underscore characters at the beginning and end of the underlined passage, like so: _example text_.

Likewise, you can mimic boldface and italics thus:

  • Use asterisks at the beginning and end of the words you want to bold — for example, *this text.*
  • Put a slash at the beginning and end of a phrase you want to italicize: /like this/.

Although you can't create true underlined, boldfaced, or italicized text in a plain-text email, these three methods are acceptable, widely understood ways of adding emphasis without the use of HTML.