🔤 Case Style Converter: camelCase, snake_case, kebab-case

What is the Programming Case Converter?

A case style converter solves a small but constant problem in programming: the same set of words has to be written a dozen different ways depending on where it lives. A "case style" (also called a naming convention) is simply a rule for joining several words into one identifier when a language will not allow spaces inside a name. The differences between styles come down to two things only: which separator joins the words, and which letters are capitalised. Everything else is the same set of words. That is why a good case style converter can show you every variant of a name side by side and let you copy the one you need in a single click.

The six styles this case style converter produces cover almost every situation you will meet. camelCase joins words with no separator and capitalises every word except the first, so getUserProfile becomes the standard form for JavaScript and Java variables. PascalCase, also called UpperCamelCase, capitalises the first word too (GetUserProfile) and is used for classes, types and React components. snake_case lowercases everything and joins with underscores (get_user_profile), the convention for Python and Rust functions and for SQL database columns. kebab-case lowercases and joins with hyphens (get-user-profile) and powers CSS class names, URL slugs and command-line flags. CONSTANT_CASE, sometimes written SCREAMING_SNAKE_CASE, uppercases everything and joins with underscores (GET_USER_PROFILE) for constants and environment variables. Title Case keeps the spaces and capitalises each word (Get User Profile) for headings and labels.

The genuinely hard part of any case style converter is not swapping the separator, it is finding the word boundaries in the first place. This tool splits the input on any run of non-alphanumeric characters (spaces, underscores, hyphens, dots, slashes) and also on camel humps, where a lowercase letter or digit is immediately followed by an uppercase letter. It handles consecutive capitals correctly too, so an acronym followed by a word such as HTMLParser splits into HTML and Parser rather than into five separate letters. Numbers attached to letters, such as v2 or 3d, are treated as their own tokens, which matches the behaviour most style guides and linters expect.

Which style you reach for depends on the language and on the kind of name you are writing. JavaScript, TypeScript, Java and C# favour camelCase for variables and methods and PascalCase for classes and types. Python and Rust use snake_case for variables and functions and CONSTANT_CASE for module-level constants. CSS classes, URL slugs and most CLI flags use kebab-case. Picking the convention your codebase already uses matters more than which one is theoretically "best": consistency is what keeps names readable, searchable and easy to refactor. A case style converter removes the friction of switching between conventions so you never introduce a typo while renaming by hand.

Because the whole conversion runs in your browser, this case style converter is fast and private. There is no upload, no account and no rate limit, so you can paste sensitive identifiers, internal field names or unreleased feature flags without worrying that anything leaves your machine. That makes it a safe everyday companion for the dozens of tiny renames that happen during code review, API design and database migrations, where copying a name correctly the first time saves a surprising amount of time.

The converter is also useful well beyond traditional code. Marketers building UTM parameters often need kebab-case or snake_case tags, data analysts cleaning column headers want consistent snake_case, and technical writers turning feature names into anchor links need clean URL slugs. Anywhere the same phrase has to appear in two different formats, a case style converter keeps the wording identical and only changes the shape, which is exactly what you want when two systems must agree on a name.

When to use it

• Renaming a variable or function from one language convention to another, for example moving a snake_case Python name into a camelCase JavaScript codebase without retyping it.
• Turning a plain English label like "Max Retry Count" into a CONSTANT_CASE constant (MAX_RETRY_COUNT) or a snake_case database column (max_retry_count).
• Generating a kebab-case CSS class name or URL slug directly from a PascalCase component name such as UserProfileCard to user-profile-card.
• Cleaning up an identifier that mixes separators, such as user-Profile_ID, into one consistent style across a whole file.
• Quickly checking how the same name looks in every convention before you commit to one when designing a new API or naming a new feature flag.
• Standardising spreadsheet or CSV column headers into snake_case before importing them into a database or a data pipeline.

How to use the Programming Case Converter

1. Type or paste your text or identifier into the input box.
2. The case style converter detects the individual words automatically from spaces, underscores, hyphens, dots and camelCase humps.
3. Read off the result in every case style at once: camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE and Title Case.
4. Click the Copy button next to the style you need to copy it to your clipboard, then paste it straight into your code or document.

Formula & method

Worked examples

The six case styles applied to the words "user profile id"

Common naming conventions by language

Separator and capitalisation rules at a glance

Common mistakes to avoid

• Splitting acronyms letter by letter. A naive converter turns HTMLParser into h_t_m_l_parser. The correct boundary keeps the acronym whole (HTML, Parser), so the result is html_parser. This case style converter detects a run of capitals followed by a capital plus lowercase and breaks there.
• Mixing conventions in one codebase. Using camelCase in some files and snake_case in others makes names harder to search and read. Pick the convention your language and project already use and apply it everywhere; the converter only helps if you stay consistent.
• Assuming kebab-case is valid as a variable name. Hyphens are subtraction in most languages, so first-name is not a legal identifier in JavaScript, Python or Java. kebab-case is for CSS classes, URL slugs and CLI flags, not in-code variable names.
• Losing digits or treating numbers oddly. Names like value2 or 3dModel sit on a boundary between letters and digits. This tool treats the number as its own token (value 2, 3 d model), which matches how most style guides and linters split them.
• Confusing CONSTANT_CASE with ordinary snake_case. They share the underscore separator, so it is easy to type max_count when you meant a constant MAX_COUNT. Reserve all-uppercase CONSTANT_CASE for true constants and environment variables, and keep snake_case lowercase for regular variables and columns.
• Starting an identifier with a digit. A token like 3dModel becomes 3dModel or 3d_model, but many languages forbid an identifier that begins with a number. Reorder the words (modelThreeD) or prefix it so the name starts with a letter before using it in code.

Glossary

camelCase

Words joined with no separator, every word capitalised except the first, for example firstName.

PascalCase

Words joined with no separator, every word including the first capitalised, for example FirstName. Also called UpperCamelCase.

snake_case

All-lowercase words joined by underscores, for example first_name.

kebab-case

All-lowercase words joined by hyphens, for example first-name. Also called dash-case or lisp-case.

CONSTANT_CASE

All-uppercase words joined by underscores, for example FIRST_NAME. Also called SCREAMING_SNAKE_CASE.

Title Case

Words kept separated by spaces with each word capitalised, for example First Name. Used for headings and labels.

Word boundary

The point where one word ends and the next begins, detected from separators or a change in letter case (a camel hump).

Identifier

A name for a variable, function, class or other entity in source code.

Slug

A URL-friendly version of a phrase, usually written in lowercase kebab-case, for example my-blog-post.

Frequently asked questions