impactvsimpairWhich spelling fits?

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

Which to use

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

#1,273
“impact” frequency rank
#31,616
“impair” frequency rank
32889
confusion score

Side-by-Side Comparison

Feature impact impair
Definition The striking of one body against another; collision. To weaken; to affect negatively; to have a diminishing effect on.

Where the eye mixes impact and impair

Muted = shared; highlighted = the visual trap. They share 4 letters in sequence. impact (VCCVCC) and impair (VCCVVC) run the same length but a different consonant-vowel pattern - the shape difference is usually the fastest tell.

6 ch
impact
6 ch
impair

Visual trap between impact and impair

These two trip readers on the page rather than in the ear: impact is /ˈɪmpækt/ while impair is /ɪmˈpɛə(ɹ)/. 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 (noun vs verb), which is usually the fastest check. Our composite confusion score for this pair is 32889, derived from the frequency rank of both members and their visual similarity.

impact is recorded at frequency rank #1,273, classified as anoun, pronounced /ˈɪmpækt/. impair is at rank #31,616, tagged as averb, pronounced /ɪmˈpɛə(ɹ)/.

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 32889, this pair ranks #334,060 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of impact vs impair

Shared letters: aimp. Private to "impact": ct. Private to "impair": r.

"impact" · 6 letters · shape VCCVCC  ·  "impair" · 6 letters · shape VCCVVC

Known mistypes of this pair

  • impact ← imapct · immpact · impacct · impactt · impatc · impcat · imppact · ipmact
  • impair ← imapir · immpair · impairr · impari · impiar · imppair · ipmair · mipair

Frequently Asked Questions

Do "impact" and "impair" mean the same thing in a sentence?
No - they are not even the same part of speech. "impact" is a noun and "impair" a verb, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "impact" or "impair"?
"impact" is the more common of the two: it sits at frequency rank #1,273 in our English list, against #31,616 for "impair". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

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 "impact" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "impair" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #334,060 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "impact" and "impair" also get mixed up with nearby pairs, the highest-scored neighbour is "impair vs impala". 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 #334,060 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