Text case conversion is one of the most common everyday tasks for writers, developers, data analysts, and SEO professionals. Whether you're formatting a headline, naming a variable, building a URL slug, or cleaning messy imported data, knowing which case style to use — and how to convert between them quickly — saves real time.
The 8 Most Common Text Case Types
1. lowercase
Every letter is lowercase. Used for: general text, email addresses, URLs, CSS properties.
Example: the quick brown fox
2. UPPERCASE
Every letter is a capital. Used for: acronyms, abbreviations, shouting in informal text, database column names in some conventions.
Example: THE QUICK BROWN FOX
3. Title Case
Principal words are capitalized; articles, short prepositions, and conjunctions are lowercase. Used for: book titles, article headlines, formal document headings, navigation labels.
Example: The Quick Brown Fox Jumps Over the Lazy Dog
4. Sentence case
Only the first word and proper nouns are capitalized. Used for: blog headings, casual writing, most modern web content.
Example: The quick brown fox jumps over the lazy dog
5. camelCase
No spaces; each word after the first starts with uppercase. Used for: JavaScript variables and functions, Java class members, API response field names.
Example: theQuickBrownFox
6. PascalCase
Like camelCase, but the first word is also capitalized. Used for: class names in most programming languages (JavaScript, TypeScript, C#, Java), React component names.
Example: TheQuickBrownFox
7. snake_case
All lowercase with underscores between words. Used for: Python variables and functions, Ruby methods, database column names, file names on Unix systems.
Example: the_quick_brown_fox
8. kebab-case
All lowercase with hyphens between words. Used for: URL slugs, HTML/CSS class names, HTML data attributes, file names in web projects.
Example: the-quick-brown-fox
Quick Reference: Which Case Style for What
- Book/film titles: Title Case
- Blog headings (modern style): Sentence case
- URL slugs: kebab-case
- CSS class names: kebab-case
- JavaScript variables: camelCase
- JavaScript class names: PascalCase
- Python variables: snake_case
- Database columns: snake_case
- Acronyms (NASA, CEO): UPPERCASE
- Email subject lines: Sentence case or Title Case
Converting Text Case Automatically
TextWonder has dedicated free tools for each case type. Here's a quick guide to all available converters:
- Uppercase Converter — convert all text to ALL CAPS
- Lowercase Converter — convert all text to lowercase
- Title Case Converter — capitalize principal words
- Sentence Case Converter — capitalize first word only
- camelCase Converter — for JavaScript and API naming
- snake_case Converter — for Python and database naming
- kebab-case Converter — for URLs and CSS class names
- URL Slug Generator — creates SEO-friendly URL slugs
All tools are free, work entirely in your browser, and require no signup. Paste text and results appear instantly.
Programming Languages and Their Preferred Case Style
Most languages have official style guides that mandate specific naming conventions:
- JavaScript/TypeScript: camelCase for variables/functions, PascalCase for classes
- Python (PEP 8): snake_case for variables/functions, PascalCase for classes
- Java: camelCase for variables/methods, PascalCase for classes
- Go: camelCase for unexported, PascalCase for exported identifiers
- Rust: snake_case for variables/functions, PascalCase for types
- CSS: kebab-case for class names and custom properties
- SQL: UPPER_SNAKE_CASE for keywords; snake_case for column names
Frequently Asked Questions
What is the difference between uppercase and title case?
Uppercase converts every letter to a capital (ALL CAPS). Title case capitalizes only the first letter of principal words — it reads normally but looks formal.
What is camelCase used for?
camelCase (also written camelCase) is used in programming for variable and function names. The first word is lowercase, subsequent words start with uppercase: myVariableName, getUserData().
What is snake_case?
snake_case uses all lowercase letters with words separated by underscores: my_variable_name. It's common in Python, Ruby, and SQL for variable and function names.
What is kebab-case?
kebab-case uses all lowercase letters with words separated by hyphens: my-variable-name. It's used in CSS class names, HTML attributes, and URL slugs.
Can I convert text case online for free?
Yes. TextWonder has free tools for every case type: uppercase, lowercase, title case, sentence case, camelCase, snake_case, kebab-case, and CONSTANT_CASE. All run in your browser with no signup.