Zellio.io

Case Converter

Convert text to UPPER, lower, Title, Sentence or camelCase.

Runs locallyWorks offlineShare link carries settings, never your data
Send output toFancy Font GeneratorOnline Diff CheckerText SummarizerBuild a workflow from thisOutput stays on this page until you send it.

Frequently asked questions

Which cases can it convert to?

UPPERCASE, lowercase, Title Case, Sentence case, camelCase and other common styles, applied instantly as you type or paste. Additional formats include kebab-case (used in URLs and filenames), snake_case (used in database column names and Python variables), and PascalCase (used in class names in most programming languages). The converter also includes other variations like CONSTANT_CASE, dot.case, and path/case for different coding and naming conventions. All transformations update live as you type or paste new text, so you can quickly find the format you need without guessing.

Is my text private?

No. Everything runs locally in your browser using standard web APIs — your text, files and inputs are never uploaded to a server, so the tool works even offline once the page has loaded.

Can I use it as a plain text pad?

Yes — paste, tidy and copy text freely. There is no account, no expiry and nothing is stored on a server, so your text stays completely private and local to your browser. You can keep the page open as long as you need and switch between case formats as many times as you like without any time limits or restrictions. The text remains in your browser until you close the page, and you can clear it manually or simply close the tab whenever you're done — nothing is saved or transmitted anywhere.

Pro tips

  • Read Title Case output before shipping it. No converter reliably knows that iPhone, McDonald's and eBay break the ordinary capitalisation rules.
  • Sentence case is the safer default for headings in most modern style guides, and it sidesteps the short-word arguments that Title Case invites.
  • Convert to lowercase before comparing or deduplicating a list of emails or usernames, since case differences create duplicates that look identical.
  • Keep an untouched copy before converting anything containing acronyms — the capitals cannot be recovered afterwards.
  • Use kebab-case for anything that becomes a URL or filename; underscores are easy to lose under a text underline and spaces need encoding.

About Case Converter

Title Case and Sentence case are the two that need checking. Short words, acronyms and proper nouns follow no single rule, so read the result before trusting it on names, brands or anything with an initialism in it.

Instantly switch text between UPPERCASE, lowercase, Title Case, Sentence case, camelCase and more. It is the fast way to fix shouty headings, normalise data, rename variables or tidy up copy pasted from different sources.

It also works as a distraction-free scratch pad: paste, transform, copy, move on. camelCase and snake_case round-trip cleanly, but Title Case does not — capitalisation rules discard information that converting back cannot recover.

Programming conventions are the other half of this job, and they are not interchangeable. camelCase belongs to JavaScript and Java variables, PascalCase to classes and components, snake_case to Python variables and database columns, SCREAMING_SNAKE_CASE to constants and environment variables, and kebab-case to URLs, CSS classes and filenames. Converting between them is constant work when data crosses a boundary — an API returning snake_case into a codebase that expects camelCase, for instance.

One direction loses information permanently. camelCase and snake_case describe the same word boundaries, so they convert back and forth cleanly. Title Case does not record where the boundaries were, and lowercasing an acronym destroys it: NASA becomes nasa, and nothing can tell a converter to restore the capitals rather than produce Nasa. Keep the original if you might need to go back.

Common use cases

  • Developers renaming variables when moving data between a snake_case API and a camelCase codebase.
  • Editors fixing a heading that arrived in all caps, without retyping it and introducing new typos.
  • Data analysts normalising a column of inconsistently capitalised names or categories before grouping on it.
  • Content teams applying a house style across a batch of titles pasted from several sources.
  • Anyone who has just realised a paragraph was typed with caps lock on and would rather not start again.
How it comparesEditors and IDEs have case commands built in, and they work on the file you happen to have open. A separate scratch pad is more convenient when the text is coming from an email, a spreadsheet or a chat message and is on its way somewhere else entirely.