Which to use
“indoor” is an adjective and “indoors” is an adverb - they look or sound alike but fill different roles in a sentence.
- #6,150
- “indoor” frequency rank
- #12,996
- “indoors” frequency rank
- 19146
- confusion score
Side-by-Side Comparison
| Feature | indoor | indoors |
|---|---|---|
| Definition | Situated in, or designed to be used in, or carried on within, the interior of a building. | Inside, into, or within a building. |
Where the eye mixes indoor and indoors
Muted = shared; highlighted = the visual trap. They share 6 letters in sequence. indoor runs 6 letters (VCCVVC) against indoors's 7 (VCCVVCC) - the length gap alone is often enough to separate them once you know to check it.
Look-alike desk: indoor vs indoors
These two trip readers on the page rather than in the ear: indoor is /ˈɪndɔː/ while indoors is /ɪnˈdɔːz/. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 extra letter(s) - “indoor” sits inside “indoors”, and the parts of speech differ too (adjective vs adverb), which is usually the fastest check. Our composite confusion score for this pair is 19146, derived from the frequency rank of both members and their visual similarity.
indoor is recorded at frequency rank #6,150, classified as anadj, pronounced /ˈɪndɔː/. indoors is at rank #12,996, tagged as anadv, pronounced /ɪnˈdɔːz/.
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 19146, this pair ranks #440,175 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.
Orthographic DNA of indoor vs indoors
Shared letters: dinor. Private to "indoor": -. Private to "indoors": s.
"indoor" · 6 letters · shape VCCVVC · "indoors" · 7 letters · shape VCCVVCC
Known mistypes of this pair
Frequently Asked Questions
Is swapping "indoor" for "indoors" ever safe?
In ordinary English text, does "indoor" or "indoors" show up more?
After this comparison
Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.
- Full dictionary entry for "indoor" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "indoors" - compare definitions side by side with the headword page. Word entry
- This pair ranks #440,175 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "indoor" and "indoors" also get mixed up with nearby pairs, the highest-scored neighbour is "indoors vs Indore". 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 #440,175 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.