fluevsfluffWhich spelling fits?

Which to use

“flue” and “fluff” are a confusable English pair: similar on the page, but distinct in meaning, check the gloss before you choose.

#38,401
“flue” frequency rank
#22,380
“fluff” frequency rank
60781
confusion score

Side-by-Side Comparison

Feature flue fluff
Definition A pipe or duct that carries gaseous combustion products away from the point of combustion (such as a furnace). Anything light, soft or fuzzy, especially fur, hair, feathers.

Where the eye mixes flue and fluff

Muted = shared; highlighted = the visual trap. They share 3 letters in sequence.

4 ch
flue
5 ch
fluff

Look-alike desk: flue vs fluff

A purely visual mix-up. flue (/fluː/) and fluff (/flʌf/) are said differently, so reading them aloud is the quickest way to catch the wrong one. On the page they stay close: they differ by 1 letter(s) in length. Our composite confusion score for this pair is 60781, derived from the frequency rank of both members and their visual similarity.

flue is recorded at frequency rank #38,401, classified as anoun, pronounced /fluː/. fluff is at rank #22,380, tagged as anoun, pronounced /flʌf/.

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 60781, this pair ranks #98,107 of 530,003 scored English confusable pairs - among the most confusable pairs.

Orthographic DNA of flue vs fluff

Shared letters: flu. Private to "flue": e. Private to "fluff": -.

"flue" · 4 letters · shape CCVV  ·  "fluff" · 5 letters · shape CCVCC

Known mistypes of this pair

  • fluefflue · fleu · fllue · lfue
  • fluffffluff · flfuf · flluff · fluf · fulff · lfuff

Frequently Asked Questions

Can "flue" and "fluff" be used interchangeably?
No. They are said differently (/fluː/ versus /flʌf/) and carry different meanings; reading the sentence aloud is usually enough to catch the wrong one.
Which is more common, "flue" or "fluff"?
"fluff" is the more common of the two: it sits at frequency rank #22,380 in our English list, against #38,401 for "flue". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

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 "flue" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "fluff" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #98,107 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "flue" and "fluff" also get mixed up with nearby pairs, the highest-scored neighbour is "flue vs fou". 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 #98,107 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