Put two tildes before and after the text. Strikethrough is not part of core CommonMark; it comes from GitHub Flavored Markdown, which nearly every modern tool follows.
All ways to write it
Two tildes on each side. GitHub Flavored Markdown and almost every editor.GitHub Flavored Markdown~~struck text~~
One tilde also works on GitHub, but not in every tool.Some tools only~struck text~
HTML fallback for strict CommonMark renderers.Needs HTML<del>struck text</del>
Example
You type
Release date: ~~Friday~~ Monday
- [x] ~~Migrate the old wiki~~You get
Release date: Friday Monday
-
Migrate the old wiki
Questions
Does strikethrough work in Slack and Discord?
Discord uses the same ~~text~~ syntax. Slack's own formatting uses a single tilde: ~text~.
Why does ~~text~~ show the tildes?
The renderer follows plain CommonMark without the GitHub extensions. Use <del>text</del> if it allows HTML.
Strikethrough in Confluence
Markdown Macro+ supports GitHub Flavored Markdown, so ~~text~~ renders struck through. Markdown Importer keeps strikethrough when it converts files into pages, and Markdown Exporter writes Confluence strikethrough back out as ~~text~~.