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Case Converter

Convert between camelCase, PascalCase, snake_case, kebab-case, Title Case, UPPER_CASE, lower case and URL slug. Nothing leaves your browser.

How Case Converter works

The case converter transforms pasted text into any of nine common casing styles: camelCase, snake_case, kebab-case, PascalCase, CONSTANT_CASE, Title Case, Sentence case, UPPER CASE and lower case. You pick the target format, click once to copy, and the conversion is done. Nothing you type or paste is transmitted anywhere; every transformation runs as a plain string operation inside your browser tab.

The conversion logic handles apostrophes, hyphens and mixed separators correctly. Sentence case capitalises only the first word and treats consecutive whitespace as a single word boundary. Title Case capitalises every word except short conjunctions and prepositions when they appear mid-phrase. The output field updates the moment you stop typing, so round-tripping through several formats takes only a few seconds.

Written by Bastien Sulyan

How to use Case Converter, step by step

  1. Paste or type the text you want to convert into the input field.
  2. Select the target casing format from the list of options.
  3. Read the converted result in the output field.
  4. Click the copy button to copy the result to your clipboard.

Common use cases

  • Convert a human-readable API field name like "user first name" to snake_case for a database column definition.
  • Reformat a list of CSS class names from kebab-case to camelCase when migrating a stylesheet to CSS-in-JS.
  • Turn a sentence-cased error message into CONSTANT_CASE for use as a TypeScript enum value.
  • Fix the casing of an auto-generated heading array so each item uses Title Case before rendering it in a UI.

Frequently asked questions

Is my text sent to any external service?

No. The casing logic is a set of pure string transformations that run inside this browser tab. The text you paste stays on your device from the moment you type it to the moment you copy the result.

How does the tool split words?

It detects boundaries at whitespace, underscores, hyphens and transitions from a lowercase letter to an uppercase letter (for inputs already in camelCase or PascalCase). For example, "myHTTPClient" splits into ["my", "HTTP", "Client"] because of the uppercase run. Accented letters and CJK characters are preserved rather than stripped: they travel with the word they belong to.

Does it preserve acronyms in camelCase and PascalCase?

Acronyms like HTTP, URL or ID are lowercased when placed mid-word in camelCase (httpClient, urlParser). This follows the most common JavaScript convention. In CONSTANT_CASE they stay fully uppercase.

Can I convert multi-line text?

Yes. Each line is converted independently, which lets you process a list of identifiers or headings in one pass. Blank lines are preserved as blank lines in the output.

What is the difference between Title Case and Sentence case?

Title Case capitalises the first letter of most words (short prepositions and conjunctions mid-phrase stay lowercase). Sentence case capitalises only the very first word of the entire input and leaves the rest as-is except for proper nouns, which you must fix manually.

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