Writing & StyleStyle guide

Comma Before Including

A comma before an “including” phrase is not automatic; punctuation can change whether the information is read as supplementary or restrictive. Chicago’s guidance makes the distinction depend on meaning, so avoid a mechanical rule that always inserts or always removes the comma.

Quick answer

Use commas around an “including” phrase when it is nonrestrictive or supplementary; omit the comma when the phrase is essential to identifying the intended set.

Key details

Core IssueA comma before an “including” phrase is not automatic; punctuation can change whether the information is read as supplementary or restrictive.
Registeredited and professional writing
RuleUse commas around an “including” phrase when it is nonrestrictive or supplementary; omit the comma when the phrase is essential to identifying the intended set.

Important caveats

Scope Boundary

Chicago’s guidance makes the distinction depend on meaning, so avoid a mechanical rule that always inserts or always removes the comma.

Further guidance

Recommendation

Use commas around an “including” phrase when it is nonrestrictive or supplementary; omit the comma when the phrase is essential to identifying the intended set.

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.

  1. Commas Q&A: comma before including — CMOS (opens in a new tab)Chicago Manual of Style · Direct style guidance on restrictive versus nonrestrictive including phrases

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