Sentence Case Converter

In short Sentence case capitalises the first letter of each sentence and lowercases the rest, which is the standard for body text everywhere and increasingly for headings too — most major publications and design systems moved to sentence case for headings because it reads faster than Title Case. The conversion is harder than it looks in one direction only. Going from Title Case or ALL CAPS to sentence case means deciding which capitals were structural and which were proper nouns, and nothing in the text records the difference. This tool preserves the pronoun "I" and recognises common proper nouns, but it will lowercase a name it does not know, so text full of people and places needs checking afterwards. Finding sentence boundaries has the same abbreviation problem every sentence tool has: "Dr. Smith arrived" contains a full stop that ends nothing, and treating it as a boundary capitalises the wrong word. Common abbreviations are handled. The safest use is on text that was ALL CAPS to begin with, where there was no capitalisation to lose.