"But" vs. "However"

"But" and "however" both serve the purpose of introducing a contrast or an opposing idea. However, they differ significantly in their grammatical function, punctuation, and level of formality.

But

Grammatical Function: "But" is a coordinating conjunction. It connects two independent clauses (complete sentences) of equal grammatical importance.

Punctuation: When "but" connects two independent clauses, it is usually preceded by a comma.
Example: I wanted to go to the beach, but it started raining.

Flexibility: "But" is typically used in the middle of a sentence. It cannot freely move to different positions within a clause.

Formality: "But" is generally more informal and conversational. It creates a smooth, direct connection between ideas.

Usage: It's often used for a direct, slight contrast.

Examples:

• She studied hard, but she still found the test difficult.
• He likes coffee, but he doesn't drink it after noon.
• The food was good, but the service was slow.

However

Grammatical Function: "However" is a conjunctive adverb. It connects two independent clauses or sentences, showing a contrasting relationship between them. It functions more like a bridge between ideas rather than a direct connector within a single sentence.

Punctuation: Punctuation rules for "however" are more flexible and depend on its position:

• At the beginning of a sentence: It's followed by a comma.
  Example: I wanted to go to the beach. However, it started raining.
• Between two independent clauses (in one sentence): It's preceded by a semicolon and followed by a comma.
  Example: I wanted to go to the beach; however, it started raining.
• In the middle of a clause: It's set off by commas on both sides.
  Example: The weather was beautiful. The trip, however, was unexpectedly expensive.
• At the end of a sentence: It's preceded by a comma.
  Example: It started raining. I went to the beach anyway, however.

Flexibility: "However" is much more flexible in its placement within a sentence or between sentences.

Formality: "However" is generally more formal and is often used in academic, professional, or more sophisticated writing. It creates a stronger pause and emphasizes the contrast more than "but."

Usage: It's used for stronger contrasts, to introduce a new perspective, or to transition between more distinct ideas.

Examples:

• She studied hard. However, she still found the test difficult.
• He likes coffee; however, he prefers tea in the evenings.
• The food was good. The service, however, was quite slow.

Key Differences Summarized

Feature	"But"	"However"
Part of Speech	Coordinating Conjunction	Conjunctive Adverb
Punctuation	Comma before it (when connecting clauses)	Semicolon before, comma after (connecting clauses); comma after (sentence start); commas around (mid-sentence)
Placement	Usually mid-sentence, between clauses	More flexible: start, middle, or end of sentence/clause
Formality	More informal, conversational	More formal, academic
Emphasis	Direct, smoother contrast	Stronger contrast, more of a pause/transition

Choosing between "but" and "however" depends on the desired tone, the specific grammatical structure, and the emphasis you want to place on the contrasting idea.