How to Bold Text in Slack (Ctrl+B / Cmd+B)

Select text in the Slack message box and press Ctrl+B — Cmd+B on macOS — to make it bold. Wrapping the words in single asterisks, like *this*, produces the same result as you type. **Slack uses asterisks where standard markdown uses two.** In CommonMark and on GitHub, single asterisks mean italic and double asterisks mean bold. Slack takes single asterisks for bold and underscores for italic. Anyone whose fingers learned the convention writing pull request descriptions will produce italics when they meant bold and be briefly confused about why. The keyboard shortcut sidesteps the whole question, which is the strongest argument for using it rather than typing the syntax. **What you type is not what anyone sees.** Slack's message box has rendered formatting live since the WYSIWYG composer arrived, so the asterisks disappear as soon as the formatting applies and the recipient never sees raw characters. This is the practical difference from a plain-text chat system where markup is only interpreted on display, and it is why a message that fails to parse in Slack looks wrong to you before you send it rather than after. **Bold works everywhere text does**, including thread replies, channel topics, message edits and the canvas editor. It does not apply inside a code block or inline code, because the point of those is that the characters are shown literally — an asterisk in a code snippet is an asterisk, not an instruction. **Combining formats works as expected.** Bold and italic can apply to the same text, giving bold italic. Bold and strikethrough combine as well. Selecting a phrase and pressing Ctrl+B then Ctrl+I is faster than working out what the nested syntax would need to be, and it avoids the specific frustration of an asterisk-underscore combination that does not parse the way you assumed. **A word on when bold actually helps.** In a channel where several people are formatting heavily, bold stops carrying emphasis and becomes visual noise — the same effect as a document where everything is highlighted. It works best on the one thing in a longer message that a skim-reader must not miss: a deadline, a decision, a name. For structure in a longer message, headings and bullet lists communicate better than bolding every line that starts a new point. **If the shortcut does nothing**, the message box does not have focus. Slack's formatting shortcuts act on the composer, and after clicking into the channel list or a message, focus is elsewhere. Clicking back into the box, or pressing Escape and then typing, restores it. The other possibility is that no text is selected — the combination toggles formatting for a selection, and pressing it with only a cursor placed in text starts bold formatting from that point rather than doing nothing visible. **Where bold does not reach.** Channel names, emoji reactions and the fields of a workflow form are all plain text — formatting applies to message bodies, thread replies, canvases and message edits, and nowhere else. Nor does bold survive being copied out to a plain-text destination: pasting a formatted Slack message into a terminal or a plain email produces the words without the asterisks, so anyone relying on the emphasis to carry meaning should make sure the sentence still reads correctly without it.