but vs by, What's the Difference?

Which to use

“but” is a conjunction and “by” is a preposition - they look or sound alike but fill different roles in a sentence.

#7,254
“but” frequency rank: #1,598
“by” frequency rank: 8852
confusion score

Side-by-Side Comparison

Feature	but	by
Definition	mas, porém, todavia	por;

Letter map: but vs by

Shared letters muted; letters that set but and by apart highlighted. Shared run: 1.

3 ch

but

2 ch

Grammar separator: but vs by

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: but is aconjunction and byapreposition. On the page they differ by 1 letter(s) in length. Our composite confusion score for this pair is 8852, derived from the frequency rank of both members and their visual similarity.

but is recorded at frequency rank #7,254, classified as aconj. by is at rank #1,598, tagged as aprep.

Glosses for this pair are partially populated in our dataset, but the full side-by-side definitions above should still guide you to the right choice.

With a confusion score of 8852, this pair ranks #64,777 of 75,631 scored Portuguese confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of but vs by

Shared letters: b. Private to "but": tu. Private to "by": y.

"but" · 3 letters · shape CVC · "by" · 2 letters · shape CV

Frequently Asked Questions

Is swapping "but" for "by" ever safe?

No - they are not even the same part of speech. "but" is a conjunction and "by" a preposition, so a sentence built for one is usually ungrammatical with the other.

Which is more common, "but" or "by"?

"by" is the more common of the two: it sits at frequency rank #1,598 in our Portuguese list, against #7,254 for "but". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

Done with this confusable. These links stay specific to "but" and "by".

Full dictionary entry for "but" with definition, IPA, and generated misspellings. Word entry
Full dictionary entry for "by" - compare definitions side by side with the headword page. Word entry
This pair ranks #64,777 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
"but" and "by" also get mixed up with nearby pairs, the highest-scored neighbour is "bué vs but". Nearby pair

Confusion rank #64,777 of 75,631 scored Portuguese pairs, corpus vintage 2026-09-03, not spelling advice.