Let's be honest – trying to underline text in Markdown feels like trying to open a pickle jar with buttered fingers. You know it should be simple, but it's weirdly frustrating. I remember spending 45 minutes on a documentation project before realizing my underlines weren't showing up. Turns out Markdown deliberately omits underlining. Why? Because back in 2004, John Gruber designed it to mimic email plain-text formatting where underlines often indicated hyperlinks.

But sometimes you just need an underline! Maybe you're writing a legal document, creating worksheets, or just want visual variety. Whatever your reason, I'll show you real solutions that work across different platforms.

Why Underlining in Markdown Isn't Straightforward

Standard Markdown doesn't have native underlining syntax. Unlike bold (**text**) or italics (*text*), there's no shortcut. Why this glaring omission? Three key reasons:

• Historical baggage: Early web browsers displayed links as underlined text by default
• Design philosophy: Markdown prioritizes readability over visual formatting
• Ambiguity prevention: Avoiding confusion between underlined text and hyperlinks

But here's the kicker – modern implementations have evolved. While pure Markdown ignores underlining, many platforms now support extensions. Let's crack this nut properly.

HTML to the Rescue: The Most Reliable Method

When I absolutely need underlines in Markdown documents, I use the HTML <u> tag. It's ugly but effective. Here's how it looks:

Regular Markdown text with <u>underlined section</u> inside.

Renders as: Regular Markdown text with underlined section inside.

Where this works:

• GitHub README files
• VS Code preview pane
• Most static site generators (Jekyll, Hugo)
• Stack Overflow posts

Where it fails:

• Some minimalist Markdown parsers like SmartyPants
• Plain-text email clients stripping HTML

Not perfect? No. But it gets the job done in 90% of cases. Better than the CSS method requiring style tags that break portability.

Platform-Specific Solutions That Actually Work

Certain flavors of Markdown added custom underline support. Here's what I've tested personally:

I switched to Typora for documentation work specifically because of formatting headaches. Their live preview handles underlining perfectly while maintaining clean Markdown underneath.

Common Underline Scenarios Solved

Academic Writing: Underlining Headings

APA format requires underlined headings? Use HTML heading tags with inline CSS:

<h3 style="text-decoration: underline;">Methodology</h3>

Works in Pandoc when converting to PDF/DOCX. Slightly messy but gets past formatting committees.

Creating Fillable PDF Forms

When generating PDFs via Pandoc, underline blank spaces like this:

Name: \underline{\hspace{4cm}}

Uses LaTeX under the hood. Requires —pdf-engine=xelatex flag.

Underlining in Tables

Got a pricing table needing emphasis? Combine HTML and Markdown:

| Item       | Price    |
|------------|----------|
| Basic Plan | $10/month |
| <u>Pro Plan</u> | <u>$25/month</u> |

Renders perfectly in GitHub and static sites. Avoid pipe characters inside the <u> tags or it breaks.

Why You Should Avoid Underlining Alternatives

You'll see folks suggesting workarounds. From experience, most create more problems:

• Bottom borders: span style="border-bottom:1px solid" – Causes line-height issues
• Underscores: ___underlined___ – Often renders as italics
• Hyperlink trickery: [text](#) – Creates fake links
• Unicode hacks: ▁U̲n̲d̲e̲r̲l̲i̲n̲e̲▁ – Breaks screen readers

/*
  Underline only headings */
.post-content h2 {
  text-decoration: underline wavy #3498db;
}