infectvsinferTell them apart

Which to use

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

#18,109
“infect” frequency rank
#23,568
“infer” frequency rank
41677
confusion score

Side-by-Side Comparison

Feature infect infer
Definition To bring (the body or part of it) into contact with a substance that causes illness (a pathogen), so that the pathogen begins to act on the body; (of a pathogen) to come into contact with (a body or body part) and begin to act on it. To introduce (something) as a reasoned conclusion; to conclude by reasoning or deduction, as from premises or evidence.

Where the eye mixes infect and infer

Muted = shared; highlighted = the visual trap. They share 4 letters in sequence.

6 ch
infect
5 ch
infer

Why the eye confuses infect with infer

A purely visual mix-up. infect (/ɪnˈfɛkt/) and infer (/ɪnˈfɜː/) 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 41677, derived from the frequency rank of both members and their visual similarity.

infect is recorded at frequency rank #18,109, classified as averb, pronounced /ɪnˈfɛkt/. infer is at rank #23,568, tagged as averb, pronounced /ɪnˈfɜː/.

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 41677, this pair ranks #256,082 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of infect vs infer

Shared letters: efin. Private to "infect": ct. Private to "infer": r.

"infect" · 6 letters · shape VCCVCC  ·  "infer" · 5 letters · shape VCCVC

Known mistypes of this pair

  • infectifnect · inefct · infcet · infecct · infectt · infetc · inffect · innfect
  • inferinefr · inferr · inffer · infre · innfer · nifer

Frequently Asked Questions

Is swapping "infect" for "infer" ever safe?
No. They are said differently (/ɪnˈfɛkt/ versus /ɪnˈfɜː/) and carry different meanings; reading the sentence aloud is usually enough to catch the wrong one.
In ordinary English text, does "infect" or "infer" show up more?
"infect" is the more common of the two: it sits at frequency rank #18,109 in our English list, against #23,568 for "infer". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

What to do next

Pronunciation already separates them, if the page still looks alike, the dictionary links below settle it.

  • Full dictionary entry for "infect" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "infer" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #256,082 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "infect" and "infer" also get mixed up with nearby pairs, the highest-scored neighbour is "infer vs infirm". 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 #256,082 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