comma with however
However as a conjunctive adverb versus however meaning “to whatever degree.”
When however means “nevertheless” and joins two independent clauses, use a semicolon before it and a comma after it: The plan failed; however, the team stayed. When it opens a sentence, follow it with a comma: However, the team stayed. When it means “to whatever degree,” do not set it off that way: However hard we tried, the lock held.
Examples
UseThe plan failed; however, the team stayed.
UseHowever hard we tried, the lock held.
AvoidThe plan failed, however the team stayed.