diffvsduffTell them apart

Quick tell: diff is a adjective, duff is a noun, so they fill different roles in a sentence.

Which to use

“diff” is an adjective and “duff” is a noun - they look or sound alike but fill different roles in a sentence.

#25,968
“diff” frequency rank
#34,065
“duff” frequency rank
60033
confusion score

Side-by-Side Comparison

Feature diff duff
Definition Difficile. Pâte à gâteau.

Where the eye mixes diff and duff

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

4 ch
diff
4 ch
duff

Visual trap between diff and duff

These two trip readers on the page rather than in the ear: diff is \dif\ while duff is \dʌf\. Spoken aloud the problem disappears. In writing it persists, because they differ by a single letter - i in “diff” becomes u in “duff”, and the parts of speech differ too (adjective vs noun), which is usually the fastest check. Our composite confusion score for this pair is 60033, derived from the frequency rank of both members and their visual similarity.

diff is recorded at frequency rank #25,968, classified as anadj, pronounced \dif\. duff is at rank #34,065, tagged as anoun, pronounced \dʌf\.

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 60033, this pair ranks #99,838 of 440,172 scored French confusable pairs - among the most confusable pairs.

Orthographic DNA of diff vs duff

Shared letters: df. Private to "diff": i. Private to "duff": u.

"diff" · 4 letters · shape CVCC  ·  "duff" · 4 letters · shape CVCC

Known mistypes of this pair

  • diffddiff · dfif · idff
  • duffdduff · dfuf · duf · udff

Frequently Asked Questions

Can "diff" and "duff" be used interchangeably?
No - they are not even the same part of speech. "diff" is an adjective and "duff" a noun, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "diff" or "duff"?
"diff" is the more common of the two: it sits at frequency rank #25,968 in our French list, against #34,065 for "duff". 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 "diff" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "duff" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #99,838 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
  • "diff" and "duff" also get mixed up with nearby pairs, the highest-scored neighbour is "duff vs dust". 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 #99,838 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.

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

Source: FrequencyWords open word-frequency list