comma with however

The punctuation of however in the sense “nevertheless” and in the sense “in whatever way” or “to whatever degree.”

Set off however with commas when however means “nevertheless.” In that sense, however is a conjunctive adverb, an adverb that relates its clause to the clause before it. A conjunctive adverb cannot join two independent clauses the way a coordinating conjunction such as but can.

The position of however in the sense “nevertheless” determines where its commas go. At the start of a sentence, however takes a comma after it: However, the permit arrived a week late. Inside a clause, a comma goes on each side: The permit, however, arrived a week late. At the end of a sentence, a comma precedes however: The permit arrived a week late, however. Opening a sentence with however in this sense is standard.

Two independent clauses linked by however need a semicolon or a period between them, because a comma alone between two independent clauses produces a comma splice. The semicolon or period goes before however, and a comma follows it: The roof was repaired; however, the gutters leak. The roof was repaired. However, the gutters leak. The semicolon belongs at the boundary between the clauses, so when however moves inside the second clause, the semicolon stays at the boundary and commas set off however: The roof was repaired; the gutters, however, leak.

However in the sense “in whatever way” or “to whatever degree” introduces a dependent clause or phrase and takes no comma after it. A comma follows the whole clause when that clause opens the sentence: However you route the cable, keep it clear of the heater. No comma precedes the clause when it follows the main clause: Arrange the chairs however you like. A phrase such as however minor in the middle of a sentence takes a comma on each side of the whole phrase: Every complaint, however minor, gets a written reply.

Examples

Use The forecast called for rain; however, the parade went ahead. (However begins the second of two independent clauses, so a semicolon precedes however and a comma follows it.)

Use However early you arrive, bring your ticket. (However means “to whatever degree” here and begins a dependent clause, so no comma follows however.)

Avoid The forecast called for rain, however, the parade went ahead. (The comma before however creates a comma splice. However cannot join two independent clauses, so a semicolon must replace the comma before however. Write The forecast called for rain; however, the parade went ahead.)

Avoid The parade however started an hour late. (The commas around however are missing. However interrupts the clause here, so a comma goes on each side. Write The parade, however, started an hour late.)