Case Converter

Key takeaways

• Nine targets: writing cases plus programming identifier styles
• camelCase humps are split correctly (getUserName → get_user_name)
• Identifier styles convert each line separately for pasted lists
• Runs client-side — your text never leaves the tab

What is a case converter?

A case converter rewrites the capitalization or identifier style of text — from prose casing like Title Case to programming styles like snake_case.

This tool handles both writing cases (upper, lower, title, sentence) and identifier styles (camel, pascal, snake, kebab, constant). Identifier styles split words on spaces, punctuation, and camelCase humps, then rejoin per line, so a pasted column of names converts in one pass.

Features

• Nine case targets

  Upper, lower, title, sentence, camel, pascal, snake, kebab, and constant.

• Smart word splitting

  Splits on spaces, punctuation, digits, and camelCase humps — acronym runs stay intact.

• Line-by-line identifiers

  Identifier styles convert each line separately, so pasted lists stay lists.

• Private conversion

  All transforms run in your browser — nothing is uploaded.

How it works

1. 1

   Paste your text

   Prose, a single identifier, or one name per line.

2. 2

   Pick a target case

   Choose a writing case or a programming identifier style.

3. 3

   Convert and copy

   Review the output pane, then copy or download the result.

Example walkthroughs

• camelCase → snake_case

  With snake_case selected, humps split into get_user_name and set_access_token.

  getUserName
  setAccessToken

• Shouting text → sentence case

  Sentence case lowercases everything, then capitalizes each sentence start.

  PLEASE REVIEW THE ATTACHED DOCUMENT. THANKS!

Use cases

• Rename API fields

  Convert a column of JSON keys between camelCase and snake_case when bridging services.

• Fix headline style

  Turn drafts into Title Case or calm down all-caps text to sentence case.

Code snippets

• snake_case in JS

  js

  The same hump-splitting regex this tool uses for identifier styles.

  const words = "getUserName".match(/[A-Z]+(?=[A-Z][a-z])|[A-Z]?[a-z]+|[A-Z]+|\d+/g);
  const snake = words.map((w) => w.toLowerCase()).join("_");
  // "get_user_name"

Common errors

• Acronyms come out wrong (h_t_t_p)

  Cause: The converter split every capital letter instead of acronym runs.

  Fix: This tool keeps runs together — HTTPResponse becomes http_response.

• Multi-line list collapsed into one identifier

  Cause: Some converters join all input words into a single output.

  Fix: Here each line converts separately; keep one name per line.

About Case Converter

Case Converter is a private workspace for changing text capitalization without retyping. Paste anything — a heading, a constants list, a CSV column of API field names — pick a target case, and convert. Writing cases (UPPERCASE, lowercase, Title Case, Sentence case) preserve punctuation and spacing, while identifier styles (camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE) split words and rejoin them the way a compiler expects.

The most common searches — “uppercase to lowercase” and “title case converter” — usually come from writers fixing shouting text or headline style. Developers arrive with a different job: renaming JSON keys between camelCase and snake_case when moving payloads between JavaScript and Python services. This tool serves both without separate utilities.

The hump-splitting rule matters more than it looks: naive converters turn “HTTPResponse” into “h_t_t_p_response”. This one keeps acronym runs together, producing “http_response”, and treats digits as their own word segments so “base64Value” round-trips sensibly.

Everything runs on-device. Identifier lists often come straight from internal schemas, so nothing is uploaded — the same privacy model as every core tool on this site. Pair it with Slug Generator when the goal is a URL rather than an identifier, or Word Counter when editing the prose you just re-cased.

Best practice: convert one style per run and spot-check acronyms and digits, since organizations differ on whether “API” stays uppercase mid-identifier.

Frequently asked questions

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