RunLocalTools

Case Converter

Paste text and instantly convert it between UPPERCASE, lowercase, Title Case, Sentence case, camelCase, PascalCase, snake_case, CONSTANT_CASE, kebab-case, and dot.case — all computed locally as you type.

Why this shows up constantly, not just occasionally

Case conversion looks like a trivial party trick until you’re staring at a spreadsheet of names in ALL CAPS that need to go into an email template, or renaming a batch of variables from snake_case to camelCase while porting code between a Python backend and a JavaScript frontend where the two languages follow opposite naming conventions by default. It’s one of those small frictions that eats five minutes of manual find-and-replace if you don’t have a tool for it, and takes five seconds if you do.

How to use it

  1. Paste your text into the input box — a single word, a full sentence, or a multi-line list.
  2. Every case format updates simultaneously in separate output panels, so you can compare them side by side rather than converting one at a time and starting over.
  3. For multi-line input, each line is converted independently, which matters if you’re processing a list of names or variable identifiers rather than a single block of prose.
  4. Click any output panel to copy just that result, or use “copy all” to grab every format at once in a labeled block.
  5. Special handling kicks in automatically for edge cases like existing acronyms (deciding whether “API” in “myAPIKey” should stay capitalized or convert to “myApiKey” is a genuinely inconsistent convention across style guides, so there’s a toggle to control this behavior).

Common situations this solves

  • Converting between programming naming conventions when porting code or data between languages with different default styles (Python’s snake_case vs. JavaScript’s camelCase vs. class names in PascalCase).
  • Cleaning up a list of names or headers exported from a spreadsheet that came through in inconsistent or all-caps formatting.
  • Generating CSS custom property names or environment variable names, which conventionally use kebab-case and CONSTANT_CASE respectively.
  • Fixing a pasted block of text that was accidentally typed with Caps Lock on, converting it back to proper Sentence case in one step.
  • Preparing a title for use as a slug base or file name, where kebab-case or snake_case is often the expected format before further processing.

Frequently asked questions

What’s the actual difference between camelCase and PascalCase? Both join words together without spaces or punctuation, capitalizing the first letter of each word — the only difference is whether the very first letter is lowercase (camelCase, common for variable and function names) or uppercase (PascalCase, common for class and component names). The distinction matters in most style guides, so mixing them up is a common but avoidable code review comment.

How does the tool decide where one “word” ends and another begins in the original text? It splits on spaces, hyphens, underscores, and case transitions (so myVariableName is correctly recognized as three words even without any separator characters), which is what allows converting cleanly between formats that don’t share the same separator convention.

Does converting to snake_case or kebab-case affect numbers or special characters? Numbers are preserved as-is and typically treated as their own word boundary (so page2Title becomes page-2-title in kebab-case), while special characters outside the standard set are generally stripped, since most of these formats are used in contexts (code identifiers, CSS classes, file names) that don’t allow arbitrary punctuation.

Can I convert an entire multi-line list at once instead of one word at a time? Yes — paste a full list with one item per line, and every line converts independently, which is the intended way to use this for cleaning up spreadsheet exports or batch-renaming style tasks rather than pasting items one at a time.

Why does my acronym get split into separate letters, like “API” becoming “A-P-I” in kebab-case? This happens when the tool interprets each capital letter as a new word boundary, which is standard behavior for most case-conversion logic but isn’t always what you want for acronyms — check the acronym-handling toggle, which treats consecutive capital letters as a single unit instead.