fuelvsfuiWhich spelling fits?

Quick tell: fuel is a noun, fui is a verb, so they fill different roles in a sentence.

Which to use

“fuel” is a noun and “fui” is a verb - they look or sound alike but fill different roles in a sentence.

#26,015
“fuel” frequency rank
#9,318
“fui” frequency rank
35333
confusion score

Side-by-Side Comparison

Feature fuel fui
Definition Variante orthographique de fioul Participe passé masculin singulier de fuir.

Where the eye mixes fuel and fui

Muted = shared; highlighted = the visual trap. They share 2 letters in sequence.

4 ch
fuel
3 ch
fui

Why the eye confuses fuel with fui

These two trip readers on the page rather than in the ear: fuel is \fjul\ while fui is \fɥi\. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 letter(s) in length, and the parts of speech differ too (noun vs verb), which is usually the fastest check. Our composite confusion score for this pair is 35333, derived from the frequency rank of both members and their visual similarity.

fuel is recorded at frequency rank #26,015, classified as anoun, pronounced \fjul\. fui is at rank #9,318, tagged as averb, pronounced \fɥi\.

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 35333, this pair ranks #277,465 of 440,172 scored French confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of fuel vs fui

Shared letters: fu. Private to "fuel": el. Private to "fui": i.

"fuel" · 4 letters · shape CVVC  ·  "fui" · 3 letters · shape CVV

Known mistypes of this pair

  • fuelfeul · ffuel · fuell · fule · ufel

Frequently Asked Questions

Can "fuel" and "fui" be used interchangeably?
No - they are not even the same part of speech. "fuel" is a noun and "fui" a verb, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "fuel" or "fui"?
"fui" is the more common of the two: it sits at frequency rank #9,318 in our French list, against #26,015 for "fuel". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.

  • Full dictionary entry for "fuel" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "fui" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #277,465 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
  • "fuel" and "fui" also get mixed up with nearby pairs, the highest-scored neighbour is "Fee vs fuel". 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 #277,465 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