Which to use
“unauthorised” and “unauthorized” are a confusable English pair: similar on the page, but distinct in meaning, check the gloss before you choose.
- #28,775
- “unauthorised” frequency rank
- #13,630
- “unauthorized” frequency rank
- 42405
- confusion score
Side-by-Side Comparison
| Feature | unauthorised | unauthorized |
|---|---|---|
| Definition | Alternative spelling of unauthorized. | Not having any authority. |
Letter map: unauthorised vs unauthorized
Shared letters muted; letters that set unauthorised and unauthorized apart highlighted. Shared run: 11.
Spelling & dictionary notes on unauthorised vs unauthorized
unauthorised and unauthorized are indexed as a confusable English pair. We have no recorded pronunciation or part of speech for both members, so the spelling overlap is what we can show you: they differ by a single letter - s in “unauthorised” becomes z in “unauthorized”. Our composite confusion score for this pair is 42405, derived from the frequency rank of both members and their visual similarity.
unauthorised is recorded at frequency rank #28,775, classified as anadj. unauthorized is at rank #13,630, tagged as anadj.
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 42405, this pair ranks #249,525 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of unauthorised vs unauthorized
Shared letters: adehinortu. Private to "unauthorised": s. Private to "unauthorized": z.
"unauthorised" · 12 letters · shape VCVVCCVCVCVC · "unauthorized" · 12 letters · shape VCVVCCVCVCVC
Known mistypes of this pair
- unauthorised ← nuauthorised · uanuthorised · unatuhorised · unauhtorised · unauthhorised · unauthoirsed · unauthoriesd · unauthorisde
- unauthorized ← nuauthorized · uanuthorized · unatuhorized · unauhtorized · unauthhorized · unauthoirzed · unauthoriezd · unauthorizde
Frequently Asked Questions
Can "unauthorised" and "unauthorized" be used interchangeably?
Which is more common, "unauthorised" or "unauthorized"?
After this comparison
You've compared "unauthorised" and "unauthorized". Here's where to go from here.
- Full dictionary entry for "unauthorised" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "unauthorized" - compare definitions side by side with the headword page. Word entry
- This pair ranks #249,525 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- 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 #249,525 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.