extensionvsTOWhich spelling fits?

Quick tell: extension is a noun, TO is an abbrev, so they fill different roles in a sentence.

Which to use

“extension” is a noun and “TO” is an abbrev - they look or sound alike but fill different roles in a sentence.

#33,032
“extension” frequency rank
#589
“TO” frequency rank
33621
confusion score

Side-by-Side Comparison

Feature extension TO
Definition Ausdehnung, Erweiterung, Umfang KFZ-Kennzeichen für Torino (Turin)

Letter map: extension vs TO

Shared letters muted; letters that set extension and TO apart highlighted. Shared run: 2.

9 ch
extension
2 ch
TO

Grammar separator: extension vs TO

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: extension is anoun and TOanabbrev. On the page they differ by 7 letter(s) in length. Our composite confusion score for this pair is 33621, derived from the frequency rank of both members and their visual similarity.

extension is recorded at frequency rank #33,032, classified as anoun, pronounced […]. TO is at rank #589, tagged as anabbrev, pronounced […].

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 33621, this pair ranks #1,681,800 of 2,006,359 scored German confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of extension vs TO

Shared letters: ot. Private to "extension": einsx. Private to "TO": -.

"extension" · 9 letters · shape VCCVCCVVC  ·  "TO" · 2 letters · shape CV

Known mistypes of this pair

  • extensionetxension · exetnsion · extenison · extennsion · extensino · extensionn · extensoin · extenssion

Frequently Asked Questions

Is swapping "extension" for "TO" ever safe?
No - they are not even the same part of speech. "extension" is a noun and "TO" an abbrev, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "extension" or "TO"?
"TO" is the more common of the two: it sits at frequency rank #589 in our German list, against #33,032 for "extension". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

Useful next steps

Done with this confusable. These links stay specific to "extension" and "TO".

  • Full dictionary entry for "extension" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "TO" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #1,681,800 of 2,006,359 scored German confusable pairs in this corpus vintage. Corpus statistics
  • "extension" and "TO" also get mixed up with nearby pairs, the highest-scored neighbour is "extension vs puzzles". 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 #1,681,800 of 2,006,359 scored German pairs, corpus vintage 2026-09-03, not spelling advice.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list