Colon Before a List
A colon can introduce a list when the lead-in strongly points forward to the items, but it is not automatic before every list. Microsoft’s style guidance varies the punctuation according to whether the introduction is a complete sentence, a fragment, or a heading.
Use a colon when the introductory wording properly sets up the list; do not add one mechanically after every heading or lead-in.
Key details
Important caveats
Complete Sentence Boundary
A complete sentence that directly announces the list can often take a colon; otherwise a period may be better.
Fragment Boundary
A fragment can take a colon when list items complete its grammar; a heading normally takes no colon.
Further guidance
Practical Application
Use a colon when the lead-in grammatically and rhetorically introduces the list. Do not insert a colon simply because a list follows; a heading normally needs no colon, while a sentence or fragment should be punctuated according to how the list completes it.
Reader Check
If the list were removed, does the introductory wording still justify a colon, or is the punctuation interrupting a verb/preposition from its complement?
Worked Example
Good: “Bring three items: a passport, the form, and a photo.” Avoid “Bring: a passport …” because the colon separates the verb from its object without a justified lead-in.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- Colons — Microsoft Style Guide (opens in a new tab)Microsoft Style Guide · House-style guidance for colons before bulleted and numbered lists
- Lists (opens in a new tab)Microsoft Style Guide · Bulleted lists for unordered related items and numbered lists for sequences or priorities