Case Changer fixes the case of any text in Google Docs™, Google Sheets™ and Google Slides™ in one click.

Highlight the text, then pick a style from the Extensions menu or the sidebar:

• UPPERCASE
• lowercase
• Sentence case (first letter of each sentence, and "i" becomes "I")
• Title Case (smart: short words like "of", "and" and "the" stay lowercase unless they start or end the title)
• Capitalize Each Word
• iNVERSE cASE
• aLtErNaTiNg cAsE
• snake_case
• kebab-case

What makes it different:

• Formatting is kept. Bold, italic, underline, colours, fonts, highlights and links stay exactly where they were.
• Works on any selection: a word, a sentence, several paragraphs, list items or whole tables.
• Fast. Change a paragraph and keep typing.
• Private. Nothing leaves your document. The add-on only asks for access to the document it is open in, and stores nothing.
• Keeps acronyms such as NASA or KL when you switch to Sentence case or Title Case, and never changes the words you list, such as iPhone, eBay or PETRONAS.
• Sentence case capitalises days, months, languages and places (Monday, Kuala Lumpur).
• Preview shows your text in all nine styles before you choose. Cycle case flips between UPPERCASE, lowercase and Title Case in one click, and your most used styles move to the top.
• Speaks your language. The sidebar, menu and messages appear in English, Bahasa Malaysia, Bahasa Indonesia, Spanish, French, German, Portuguese, Italian, Dutch, Tagalog, Turkish or Greek, following your Google account language.
• Title Case knows which small words to keep lowercase in each of those languages. It detects the language from the text itself, or you can choose it, and you can add your own words.
• Gets Turkish and Greek right: dotted and dotless i, and the final sigma.
• Nothing selected? Change the whole document, sheet or presentation in one go, including footnotes in Google Docs™ and speaker notes in Google Slides™. Select a whole column in Google Sheets™ and the header row is left alone.
• Free, with no account, sign-up or ads.

Tip: made a mistake? Press Cmd+Z or Ctrl+Z to undo, just like any other edit.

Works in Google Docs™ (selected text), Google Sheets™ (selected cells; formulas, numbers and dates are never touched) and Google Slides™ (highlighted text, text boxes, shapes and tables).

Google Docs™, Google Sheets™, Google Slides™ and Google Workspace™ are trademarks of Google LLC.