Writing & StyleRule guide

Comma Splice

A comma splice is a sentence-boundary error in which a comma alone joins independent clauses. The repair depends on the relationship between the clauses: use a period, a semicolon, or a comma plus an appropriate coordinating conjunction.

Quick answer

A comma splice occurs when two independent clauses are joined with only a comma. Standard repairs include separating the clauses, using a semicolon, or adding an appropriate coordinating conjunction after the comma.

Key details

Core Issuejoining independent clauses with comma alone
Registergeneral, academic, and professional writing
Rule Familysentence boundaries and punctuation

Important caveats

Scope Boundary

Not every comma between clauses is a splice: a comma can be correct when a coordinating conjunction links the independent clauses or when the clause structure is different.

Further guidance

Application

Repair a comma splice with a period, a semicolon, or a comma plus a coordinating conjunction such as “and,” “but,” or “so,” as the meaning requires.

Core Rule

Do not use a comma by itself to join two independent clauses in standard edited prose.

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. Run-ons, Comma Splices, and Fused Sentences — Purdue OWL (opens in a new tab)Purdue Online Writing Lab · University writing-center guidance defining comma splices and showing standard repairs for independent clauses.

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