Browser-local text utility

Case Converter

Convert text to uppercase, lowercase, General Title Case, sentence case, or toggle case. These modes consolidate the major case-conversion jobs without pretending to implement a named editorial style guide.

Enter text and choose an action.

Method and example

Uppercase and lowercase use the browser’s locale-aware default transforms. General Title Case lowercases text, then capitalizes the first letter of each Unicode word. Sentence case lowercases text and capitalizes the first alphabetic character at the start and after period, question mark, or exclamation mark.

Worked example

hello WORLD becomes HELLO WORLD, hello world, Hello World, or Hello world depending on the selected mode. Mother-in-law becomes Mother-In-Law under the general title rule.

Behavior and limits

  • General Title Case is deterministic, not AP, Chicago, or MLA style.
  • Sentence case is a punctuation heuristic and does not understand abbreviations such as Dr. or U.S.
  • Apostrophes remain inside words; hyphenated segments are capitalized separately.
  • Unicode casing varies where browser and language rules differ.

Common mistakes

  • Assuming automatic title case follows a publisher’s house style
  • Expecting abbreviation-aware sentence detection
  • Using styled Unicode when ordinary case conversion is intended
  • Rendering untrusted text as HTML

Large-text handling

Character counting, case conversion, and reversal accept up to 5,000,000 UTF-16 code units and run only after an explicit action. Morse translation uses a lower 100,000-character text limit because encoded output can expand substantially.