Bold, italic, and strikethrough in Markdown

In Markdown, wrap text in double asterisks for bold (**word**), single asterisks or underscores for italic (*word*), and double tildes for strikethrough (~~word~~). All three are inline marks, so they work mid-sentence around a word or a phrase.

Every one follows the same shape: a marker before the text, the same marker after it.

Bold

Put two asterisks on each side of the text you want bold.

Pack a charger, a passport, and **the tickets**.

That renders as: Pack a charger, a passport, and the tickets.

You can also use two underscores, __like this__, and get the same result. Asterisks are the common choice, so pick one and stay consistent across a file.

Italic

Put one asterisk on each side. Or one underscore. Either works.

She said it was *fine*, which clearly meant the opposite.

That renders as: She said it was fine, which clearly meant the opposite.

One asterisk is italic, two is bold, and three is both. So ***this*** is bold and italic at once. Worth knowing, but you'll rarely need it.

Underscores have a useful quirk. A single underscore inside a word, like file_name_here, won't turn italic in most parsers. That's exactly what you want when you're writing about code or filenames. Asterisks mid-word are less predictable, so prefer underscores when the text already has underscores in it.

Strikethrough

Put two tildes on each side. The tilde is the ~ key, usually top-left on the keyboard.

Deadline is ~~Friday~~ Monday.

That renders as: Deadline is Friday Monday.

Strikethrough isn't part of the original CommonMark spec. It comes from GitHub Flavored Markdown (GFM), the extended flavor GitHub uses, and it's now supported almost everywhere. Most editors and sites render it. A few strict CommonMark-only parsers won't, and you'll see the raw ~~text~~ instead. If a tool ignores your strikethrough, that's why.

Combining them

The marks nest, so you can stack bold and italic, or strike through bold text.

This is **bold with *italic* inside it**.
The price is ~~**$40**~~ now $25.

The first line renders the inner word in italic while the whole phrase stays bold. The second strikes through the bold $40.

In Unmarked

All three render. Bold, italic, and strikethrough all display the way you'd expect in Read mode, since Unmarked parses CommonMark plus the GitHub extensions, and strikethrough is one of those.

In Write mode you see bold text as bold and struck text as struck. The **, *, and ~~ fade back until your cursor lands on the line, so they're there to edit the moment you need them and out of the way the rest of the time.

There are shortcuts too: ⌘B for bold and ⌘I for italic wrap the selected text for you, so you don't have to type the markers by hand.