BMIvsbutWhich spelling fits?

Quick tell: BMI is a noun, but is a preposition, so they fill different roles in a sentence.

Which to use

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

#16,419
“BMI” frequency rank
#25
“but” frequency rank
16444
confusion score

Side-by-Side Comparison

Feature BMI but
Definition Initialism of body mass index. Apart from, except (for), excluding.

Letter map: BMI vs but

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

3 ch
BMI
3 ch
but

Role in the sentence - BMI and but

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: BMI is anoun and butapreposition. On the page they share most of their letters but differ in 2 positions. Our composite confusion score for this pair is 16444, derived from the frequency rank of both members and their visual similarity.

BMI is recorded at frequency rank #16,419, classified as anoun. but is at rank #25, tagged as aprep, pronounced /ˈbʌt/.

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 16444, this pair ranks #457,704 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of BMI vs but

Shared letters: b. Private to "BMI": im. Private to "but": tu.

"BMI" · 3 letters · shape CCV  ·  "but" · 3 letters · shape CVC

Frequently Asked Questions

Can "BMI" and "but" be used interchangeably?
No - they are not even the same part of speech. "BMI" is a noun and "but" a preposition, so a sentence built for one is usually ungrammatical with the other.
Frequency check: "BMI" vs "but" - which ranks higher?
"but" is the more common of the two: it sits at frequency rank #25 in our English list, against #16,419 for "BMI". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

After this comparison

You've compared "BMI" and "but". Here's where to go from here.

  • Full dictionary entry for "BMI" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "but" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #457,704 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "BMI" and "but" also get mixed up with nearby pairs, the highest-scored neighbour is "BFS vs BMI". Nearby pair

Confusion rank #457,704 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list