cosvscostWhich spelling fits?

Quick tell: cos is a pronoun, cost is a noun, so they fill different roles in a sentence.

Which to use

“cos” is a pronoun and “cost” is a noun - they look or sound alike but fill different roles in a sentence.

#27,810
“cos” frequency rank
#22,928
“cost” frequency rank
50738
confusion score

Side-by-Side Comparison

Feature cos cost
Definition qualquer coisa custo

Letter map: cos vs cost

Shared letters muted; letters that set cos and cost apart highlighted. Shared run: 3. cos runs 3 letters (CVC) against cost's 4 (CVCC) - the length gap alone is often enough to separate them once you know to check it.

3 ch
cos
4 ch
cost

Role in the sentence - cos and cost

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: cos is apronoun and costanoun. On the page they differ by 1 extra letter(s) - “cos” sits inside “cost”. Our composite confusion score for this pair is 50738, derived from the frequency rank of both members and their visual similarity.

cos is recorded at frequency rank #27,810, classified as apron. cost is at rank #22,928, tagged as anoun, pronounced /ˈkɔst/.

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 50738, this pair ranks #14,228 of 75,631 scored Portuguese confusable pairs - among the most confusable pairs.

Orthographic DNA of cos vs cost

Shared letters: cos. Private to "cos": -. Private to "cost": t.

"cos" · 3 letters · shape CVC  ·  "cost" · 4 letters · shape CVCC

Known mistypes of this pair

  • cost ← ccost · cosst · costt · cots · csot · ocst

Frequently Asked Questions

Can "cos" and "cost" be used interchangeably?
No - they are not even the same part of speech. "cos" is a pronoun and "cost" a noun, so a sentence built for one is usually ungrammatical with the other.
Frequency check: "cos" vs "cost" - which ranks higher?
"cost" is the more common of the two: it sits at frequency rank #22,928 in our Portuguese list, against #27,810 for "cos". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

What to do next

Done with this confusable. These links stay specific to "cos" and "cost".

  • Full dictionary entry for "cos" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "cost" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #14,228 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
  • "cos" and "cost" also get mixed up with nearby pairs, the highest-scored neighbour is "coin vs cos". Nearby pair
  • Recorded mistypes exist for at least one side of this pair, useful when a spell-checker or OCR lands on the wrong form. See mistypes

Confusion rank #14,228 of 75,631 scored Portuguese pairs, corpus vintage 2026-09-03, not spelling advice.

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

Source: FrequencyWords open word-frequency list