proofvspropWhich spelling fits?

Which to use

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

#2,052
“proof” frequency rank
#10,112
“prop” frequency rank
12164
confusion score

Side-by-Side Comparison

Feature proof prop
Definition An effort, process, or operation designed to establish or discover a fact or truth; an act of testing; a test; a trial. An object placed against or under another, to support it; anything that supports.

Where the eye mixes proof and prop

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

5 ch
proof
4 ch
prop

Visual trap between proof and prop

A purely visual mix-up. proof (/pɹuːf/) and prop (/pɹɒp/) 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 12164, derived from the frequency rank of both members and their visual similarity.

proof is recorded at frequency rank #2,052, classified as anoun, pronounced /pɹuːf/. prop is at rank #10,112, tagged as anoun, pronounced /pɹɒp/.

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 12164, this pair ranks #483,100 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of proof vs prop

Shared letters: opr. Private to "proof": f. Private to "prop": -.

"proof" · 5 letters · shape CCVVC  ·  "prop" · 4 letters · shape CCVC

Known mistypes of this pair

  • proofporof · pproof · prof · profo · prooff · prroof · rpoof
  • propporp · pprop · propp · prpo · prrop · rpop

Frequently Asked Questions

Is swapping "proof" for "prop" ever safe?
No. They are said differently (/pɹuːf/ versus /pɹɒp/) and carry different meanings; reading the sentence aloud is usually enough to catch the wrong one.
Which is more common, "proof" or "prop"?
"proof" is the more common of the two: it sits at frequency rank #2,052 in our English list, against #10,112 for "prop". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

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 "proof" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "prop" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #483,100 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "proof" and "prop" also get mixed up with nearby pairs, the highest-scored neighbour is "poops vs prop". 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 #483,100 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