Which to use
“fact” is a noun and “fast” is an adverb - they look or sound alike but fill different roles in a sentence.
- #30,550
- “fact” frequency rank
- #8,052
- “fast” frequency rank
- 38602
- confusion score
Side-by-Side Comparison
| Feature | fact | fast |
|---|---|---|
| Definition | facto ^((português europeu)) ou fato ^((português do Brasil)) | quase |
Where the eye mixes fact and fast
Muted = shared; highlighted = the visual trap. They share 3 letters in sequence.
Visual trap between fact and fast
These two trip readers on the page rather than in the ear: fact is /ˈfækt/ while fast is /fast/. Spoken aloud the problem disappears. In writing it persists, because they differ by a single letter - c in “fact” becomes s in “fast”, and the parts of speech differ too (noun vs adverb), which is usually the fastest check. Our composite confusion score for this pair is 38602, derived from the frequency rank of both members and their visual similarity.
fact is recorded at frequency rank #30,550, classified as anoun, pronounced /ˈfækt/. fast is at rank #8,052, tagged as anadv, pronounced /fast/.
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 38602, this pair ranks #27,810 of 75,631 scored Portuguese confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of fact vs fast
Shared letters: aft. Private to "fact": c. Private to "fast": s.
"fact" · 4 letters · shape CVCC · "fast" · 4 letters · shape CVCC
Known mistypes of this pair
Frequently Asked Questions
Can "fact" and "fast" be used interchangeably?
Which is more common, "fact" or "fast"?
Useful next steps
Eye-level mix-up between "fact" and "fast" is sorted above. Next: full entries or other pairs that share a letter shape.
- Full dictionary entry for "fact" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "fast" - compare definitions side by side with the headword page. Word entry
- This pair ranks #27,810 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
- "fact" and "fast" also get mixed up with nearby pairs, the highest-scored neighbour is "fact vs fava". 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 #27,810 of 75,631 scored Portuguese pairs, corpus vintage 2026-09-03, not spelling advice.