Case Converter
Convert your text to any case format instantly. Type or paste text below and pick a conversion style.
About This Tool
The Case Converter transforms text between nine popular case formats including UPPERCASE, lowercase, Title Case, camelCase, snake_case, and more. It is ideal for developers formatting variable names, writers adjusting headings, or anyone who needs quick text transformations without manual retyping.
Last updated: April 21, 2026· Reviewed by the CalcNeeds Team
About This Calculator
This case converter instantly transforms text between uppercase, lowercase, Title Case, Sentence case, camelCase, PascalCase, snake_case, kebab-case, and other common formats. Paste or type your text, click the style you need, and copy the result. It handles multi-line input, mixed formatting, and special characters without losing content.
Developers use case conversion constantly — renaming variables, formatting API keys, converting database column names, or preparing strings for URL slugs. Writers and editors need it for headline capitalization and style-guide compliance. Instead of retyping text manually, this tool makes the transformation instant and error-free.
Everything runs in your browser. No text is sent to a server, so you can safely convert proprietary code, passwords, or confidential copy without concern.
camelCase vs snake_case vs kebab-case vs PascalCase
camelCase starts with a lowercase letter and capitalizes the first letter of each subsequent word: getUserName, totalItemCount. It is the dominant convention for variables and functions in JavaScript, TypeScript, and Java.
PascalCase (also called UpperCamelCase) capitalizes every word, including the first: GetUserName, TotalItemCount. It is the standard for class names in most object-oriented languages and for React component names.
snake_case joins words with underscores and keeps everything lowercase: get_user_name, total_item_count. Python, Ruby, and Rust use snake_case for variables and functions. Database column names and environment variables also commonly use this style.
kebab-case joins words with hyphens: get-user-name, total-item-count. CSS class names, URL slugs, and CLI flags almost always use kebab-case because hyphens are URL-safe and visually distinct.
Naming conventions by programming language
JavaScript and TypeScript: camelCase for variables and functions, PascalCase for classes and React components, UPPER_SNAKE_CASE for constants. File names vary — some teams use kebab-case (user-profile.ts), others use PascalCase for component files (UserProfile.tsx).
Python:snake_case for variables, functions, and module names; PascalCase for classes; UPPER_SNAKE_CASE for constants. PEP 8, Python's official style guide, codifies these rules and most linters enforce them automatically.
Java and C#: camelCase for variables and method parameters, PascalCase for class names and public methods (C# uses PascalCase for all public members). Java packages use all-lowercase dot-separated names like com.example.project.
CSS: kebab-case is the universal standard for class names, IDs, and custom properties (--primary-color). BEM methodology extends this with double hyphens and underscores: block__element--modifier.
Title Case rules and style guides
Title Case capitalizes the first and last words of a title and all major words in between. Minor words — articles (a, an, the), short conjunctions (and, but, or), and short prepositions (in, on, at, to, for) — stay lowercase unless they begin or end the title.
Different style guides define "minor words" slightly differently. AP style lowercases prepositions under four letters. Chicago Manual of Style lowercases prepositions regardless of length. APA capitalizes words of four or more letters. If your organization follows a specific guide, verify its exact rules.
Common mistakes include capitalizing every word (that is Start Case, not Title Case), lowercasing the first word after a colon, and capitalizing short verbs like "is" and "be" — these should actually be capitalized because they are verbs, not prepositions.
Sentence case and when to use it
Sentence case capitalizes only the first word and proper nouns, just like a regular sentence: "How to convert text between case styles." It is the standard for body text, UI labels in most design systems (Google Material Design specifies sentence case for buttons and labels), and many blog-style headlines.
Sentence case is easier to read in long lists and navigation menus because the eye can scan it quickly without the visual interruption of capital letters. It also eliminates ambiguity about which words to capitalize, reducing editorial errors.
The main drawback is that sentence case can look informal in contexts where Title Case is expected, such as book titles, newspaper headlines, and formal reports. Choose based on your audience and medium.
UPPER_SNAKE_CASE and other special formats
UPPER_SNAKE_CASE (also called SCREAMING_SNAKE_CASE or CONSTANT_CASE) is used for constants and environment variables across nearly every language: MAX_RETRIES, API_BASE_URL, DATABASE_HOST. The all-caps styling signals that the value should not be reassigned.
dot.case appears in Java package names, configuration keys (server.port), and some logging frameworks. Train-Case (capitalizing each word in kebab-case) shows up in HTTP headers like Content-Type and X-Request-Id, though HTTP/2 lowercases headers in transit.
When migrating data between systems — say, converting a JSON API response with camelCase keys into a Python dictionary with snake_case keys — consistent case conversion prevents subtle bugs and keeps your codebase idiomatic in each language.
Frequently Asked Questions
What is camelCase and where is it used?
camelCase starts with a lowercase letter and capitalizes the first letter of each subsequent word, with no separators: myVariableName. It is the standard naming convention for variables and functions in JavaScript, TypeScript, Java, and Swift.
What is the difference between camelCase and PascalCase?
The only difference is the first letter. camelCase starts lowercase (getUserName), while PascalCase starts uppercase (GetUserName). PascalCase is used for class names in most languages and for React component names. camelCase is used for variables and functions.
When should I use snake_case vs kebab-case?
Use snake_case for Python variables, Ruby methods, database column names, and environment variables. Use kebab-case for CSS class names, URL slugs, HTML attributes, and CLI flags. The choice is usually dictated by the language or platform you are working in.
What is Title Case vs Sentence case?
Title Case capitalizes major words (The Quick Brown Fox Jumps Over the Lazy Dog). Sentence case capitalizes only the first word and proper nouns (The quick brown fox jumps over the lazy dog). Title Case is for headlines and titles; sentence case is for UI labels, body text, and casual headlines.
Which case style should I use for CSS class names?
kebab-case is the universal standard for CSS class names (e.g., .nav-bar, .btn-primary). If you use a methodology like BEM, you extend kebab-case with underscores and double hyphens: .card__title--highlighted. Avoid camelCase in CSS as it conflicts with CSS conventions.
How do I convert camelCase to snake_case in Python?
You can use a regex: re.sub(r'(?<=[a-z0-9])(?=[A-Z])', '_', text).lower(). This inserts an underscore before each capital letter that follows a lowercase letter or digit, then lowercases the result. Or simply paste your text into this case converter for instant results.
What case does Python use for variable names?
Python uses snake_case for variables, functions, and method names; PascalCase for class names; and UPPER_SNAKE_CASE for constants. These conventions are defined in PEP 8, Python's official style guide, and are enforced by linters like flake8 and pylint.
What is SCREAMING_SNAKE_CASE used for?
SCREAMING_SNAKE_CASE (also called CONSTANT_CASE) is used for constants and environment variables in virtually every programming language. Examples include MAX_RETRIES, API_BASE_URL, and NODE_ENV. The all-caps styling signals that the value is a constant and should not change.
How do I capitalize a title correctly in AP style?
In AP style, capitalize the first and last words and all major words. Lowercase articles (a, an, the), coordinating conjunctions (and, but, or, for, nor), and prepositions of three letters or fewer (in, on, at, to, by). Always capitalize verbs, even short ones like 'is' and 'be'.
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