What is Text Case?
Text case refers to the capitalisation pattern applied to letters in a word or phrase. Different contexts — formal writing, web development, databases, URLs, social media — each have their own case conventions, and mixing them up causes confusion, broken code, or inconsistent branding.
Converting between cases manually is tedious and error-prone, especially for long strings or when switching between multiple conventions in the same project. A case converter automates the process in a single click.
Convert text to any case instantly — UPPERCASE, camelCase, snake_case, and 7 more. Free, no sign-up.
Open Case Converter →All Case Types Explained
Here's every major case type at a glance, with colour-coded groupings for writing and developer use:
Writing Cases
UPPERCASE
Every letter is capitalised. Use it sparingly — all-caps text is harder to read than mixed case and can feel aggressive in prose. Best used for: abbreviations (NASA, HTML, API), short headings where impact matters, warning labels, and button text in some design systems.
lowercase
All letters lower. Used in URLs, domain names, most code identifiers, and casual digital communication. Some brands use all-lowercase for their names (e.g. adidas, instagram) as a deliberate style choice.
Title Case
The first letter of every word is capitalised. Used for article headlines, page titles, book names, product names, and formal document headings. Different style guides (AP, Chicago, APA) have slightly different rules about which words to capitalise — see the Title Case Rules section below.
Sentence case
Only the first word of each sentence and proper nouns are capitalised — exactly like normal prose. This is the most common case for body text, email subjects, UI labels, and modern product copy. Most major tech companies (Google, Apple, Notion) now use Sentence case for UI headings rather than Title Case.
When in doubt between Title Case and Sentence case for a heading: if it's a formal document or publication, use Title Case. If it's a web page, app UI, or blog post, Sentence case is the modern standard.
Developer Cases
camelCase
Words are joined with no separator. The first word is all lowercase; every subsequent word starts with a capital letter. The capital letters in the middle resemble a camel's humps — hence the name.
Used in: JavaScript, Java, Swift, Kotlin — variable names, function names, method names, object properties.
PascalCase (UpperCamelCase)
Identical to camelCase except the first word is also capitalised. Every word starts with an uppercase letter with no separators.
Used in: Class names in C#, Java, TypeScript, Python. React component names. Constructor functions.
Quick rule: myFunction() is camelCase — it's a function call. MyComponent is PascalCase — it's a class or React component.
snake_case
All lowercase, words separated by underscores. Named after the way the text "slithers" along the ground with no capital humps.
Used in: Python (variables, functions, file names), Ruby, PostgreSQL/MySQL column names, JSON keys in some APIs, environment variable names in lowercase.
kebab-case
All lowercase, words separated by hyphens. Named because the words are "skewered" like kebab ingredients on a stick.
Used in: CSS class names, HTML data attributes, URL slugs, npm package names, YAML configuration keys, HTML file names.
Both are all-lowercase. Use snake_case in Python and databases. Use kebab-case in CSS, HTML, and URLs. The hyphen in kebab-case is invalid in most programming language identifiers, but valid in CSS and HTML.
When to Use Each Case — Quick Reference
| Case | Example | Primary use | Context |
|---|---|---|---|
| UPPERCASE | API_KEY | Constants, abbreviations, env vars | Dev Writing |
| lowercase | username | URLs, general identifiers | Dev |
| Title Case | The Quick Brown Fox | Article titles, book names, formal headings | Writing |
| Sentence case | The quick brown fox | Body text, UI labels, blog headings | Writing |
| camelCase | getUserData() | Variables, functions in JS/Java/Swift | Dev |
| PascalCase | UserProfile | Classes, React components, constructors | Dev |
| snake_case | user_id | Python vars, DB columns, file names | Dev |
| kebab-case | nav-bar | CSS classes, URL slugs, HTML attrs | Dev |
Live Case Converter Demo
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Title Case Rules by Style Guide
Title Case isn't simply "capitalise every word" — different style guides have different rules about which words to skip. The main ones to know:
- AP Style (journalism) — capitalise all words except articles (a, an, the), short prepositions (in, of, at), and coordinating conjunctions (and, but, or) — unless they're the first or last word.
- Chicago Manual of Style — similar to AP but also capitalises prepositions of four or more letters (Between, Through, With).
- APA Style (academic) — capitalise all major words. Lowercase only articles, short prepositions, and coordinating conjunctions.
- MLA Style — capitalise all words except articles, prepositions, coordinating conjunctions, and the "to" in infinitives — unless they're the first or last word.
For blog posts and web content, use our Case Converter's Title Case mode — it handles the standard rules automatically. For academic papers, check your institution's specific style guide.
Frequently Asked Questions
Conclusion
Text case is one of those small details that separates professional writing from careless copy, and working code from broken identifiers. Knowing when to use Title Case vs Sentence case for headings, camelCase vs PascalCase for identifiers, and snake_case vs kebab-case for separators makes your work consistent and readable.
Our free Case Converter handles all ten case types in one place — paste any text, click the target case, and copy the result. No manual editing required.
Convert text to any case — 10 options including camelCase, snake_case, kebab-case and more. Free.
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