Which to use
“what” is a pronoun and “when” is an adverb - they look or sound alike but fill different roles in a sentence.
- #4,752
- “what” frequency rank
- #8,658
- “when” frequency rank
- 13410
- confusion score
Side-by-Side Comparison
| Feature | what | when |
|---|---|---|
| Definition | was? | wann |
Where the eye mixes what and when
Muted = shared; highlighted = the visual trap. They share 2 letters in sequence. what and when follow the identical consonant-vowel pattern (CCVC). Same shape at a glance is often the real trap, independent of shared letters.
Visual trap between what and when
These two trip readers on the page rather than in the ear: what is [wɒt] while when is [wɛn]. Spoken aloud the problem disappears. In writing it persists, because they share most of their letters but differ in 2 positions, and the parts of speech differ too (pronoun vs adverb), which is usually the fastest check. Our composite confusion score for this pair is 13410, derived from the frequency rank of both members and their visual similarity.
what is recorded at frequency rank #4,752, classified as apron, pronounced [wɒt]. when is at rank #8,658, tagged as anadv, pronounced [wɛn].
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 13410, this pair ranks #1,958,173 of 2,006,359 scored German confusable pairs - a relatively easy-to-tell-apart pair.
Orthographic DNA of what vs when
Shared letters: hw. Private to "what": at. Private to "when": en.
"what" · 4 letters · shape CCVC · "when" · 4 letters · shape CCVC
Known mistypes of this pair
Frequently Asked Questions
Can "what" and "when" be used interchangeably?
Which is more common, "what" or "when"?
What to do next
Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.
- Full dictionary entry for "what" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "when" - compare definitions side by side with the headword page. Word entry
- This pair ranks #1,958,173 of 2,006,359 scored German confusable pairs in this corpus vintage. Corpus statistics
- "what" and "when" also get mixed up with nearby pairs, the highest-scored neighbour is "went vs when". 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 #1,958,173 of 2,006,359 scored German pairs, corpus vintage 2026-09-03, not spelling advice.