Case Converter
Convert text between UPPER, lower, Title Case, Sentence case, camelCase, snake_case, kebab-case, and 8 more modes. Live preview, copy, download.
Need a specific publication style? Each guide has its own preposition cutoff, conjunction handling, and article rules:
- Title Case Converter (generic 4-letter preposition rule, the default for most editors).
- AP Title Case (soon) (newsroom standard, lowercase prepositions of 3 letters or fewer).
- APA Title Case (soon) (academic; capitalize words of 4+ letters).
- MLA Title Case (soon) (humanities; capitalize all principal words).
- Chicago Title Case (soon) (book and journal standard, headline-style capitalization).
How to use the case converter
1. Paste or type your text
Drop the text into the input box on the left. The output box updates live on every keystroke. Nothing leaves your browser; conversion runs locally in JavaScript.
2. Pick a mode
Click any pill above the input. Basic modes (UPPER, lower, Title, Sentence) handle everyday writing. Programming modes (camelCase, snake_case, kebab-case, dot.case, PascalCase, CONSTANT_CASE, Path/Case) handle identifiers and slugs. Novelty modes (aLtErNaTiNg, iNVERSE) handle social posts and meme text.
3. Pick a style guide (Title Case only)
When Title Case is the active mode, the sidebar shows a ruleset dropdown. Generic uses the 4-letter rule (the default in most editors). AP, APA, MLA, Chicago, and NY Times each handle prepositions, conjunctions, and articles a little differently. Pick the one your publication or class requires. The spoke pages linked above carry the full ruleset for each style.
4. Copy or download
Click Copy to put the output on the clipboard. Click Download to save it as a .txt file. The Quick Swap button moves the output back into the input so you can chain conversions (Title Case, then snake_case, for example).
Case styles explained
Same source sentence, every mode applied. Skim the right column to match a mode to the look you need.
| Mode | Example output | Typical use |
|---|---|---|
| UPPER CASE | THE QUICK BROWN FOX | Headlines, signage, emphasis. |
| lower case | the quick brown fox | Stylistic body text, URLs. |
| Title Case | The Quick Brown Fox | Headlines, book titles, article titles. |
| Sentence case | The quick brown fox | Body copy, captions, subheadings. |
| camelCase | theQuickBrownFox | JavaScript, Java variable names. |
| PascalCase | TheQuickBrownFox | Class names, React components, types. |
| snake_case | the_quick_brown_fox | Python, Ruby, database columns. |
| kebab-case | the-quick-brown-fox | CSS classes, URL slugs, HTML attributes. |
| dot.case | the.quick.brown.fox | Config keys, namespaces, version tags. |
| Path/Case | The/Quick/Brown/Fox | URL paths, file paths. |
| CONSTANT_CASE | THE_QUICK_BROWN_FOX | Environment variables, constants. |
| aLtErNaTiNg | tHe QuIcK bRoWn FoX | Social posts, meme text. |
| iNVERSE cASE | THE qUICK bROWN fOX | Swap-case effect, novelty. |
Title case style guides
"Title Case" is not one rule, it is five. Each publication standard treats short words (prepositions, conjunctions, articles) a little differently. Pick the one your editor, professor, or platform expects.
| Style | Preposition rule | Conjunctions | Articles | Spoke page |
|---|---|---|---|---|
| Generic | Lowercase if 3 letters or fewer (of, on, in, to) | Lowercase: and, but, or, nor | Lowercase: a, an, the | Title Case Converter |
| AP | Lowercase if 3 letters or fewer | Lowercase: and, but, or, nor, for, yet, so | Lowercase: a, an, the | AP page (soon) |
| APA | Capitalize words of 4+ letters; major words always capitalized | Lowercase: and, but, or, nor | Lowercase: a, an, the (mid-title) | APA page (soon) |
| MLA | Lowercase all prepositions regardless of length | Lowercase: and, but, or, nor, yet, so | Lowercase: a, an, the (mid-title) | MLA page (soon) |
| Chicago | Lowercase all prepositions regardless of length | Lowercase: and, but, or, nor, for, so, yet | Lowercase: a, an, the (mid-title) | Chicago page (soon) |
| NY Times | Lowercase prepositions of 3 letters or fewer, plus "of", "to", "in" | Lowercase: and, but, or, nor | Lowercase: a, an, the (mid-title) | NYT page (soon) |
First-word and last-word capitalization is universal across all five styles. The differences live in the middle of the title.
When to use which case
Programming naming conventions
Most languages and frameworks ship with strong conventions. Following them is not just style, it is what linters, IDE auto-imports, and code reviewers expect.
- camelCase: JavaScript variables and functions, Java methods and fields, Swift variables, Kotlin properties.
- PascalCase: class names in most languages, React and Vue components, TypeScript types and interfaces, C# methods.
- snake_case: Python variables and functions, Ruby methods, Rust functions, SQL column names, JSON keys in many APIs.
- kebab-case: CSS classes and custom HTML attributes, URL slugs, npm package names, file names in many static sites.
- CONSTANT_CASE: environment variables (DATABASE_URL), language-level constants (MAX_RETRIES), Makefile variables.
- dot.case: configuration keys (server.port), versioned identifiers (v1.2.3), namespace separators.
Editorial styling
Choosing between Title Case and Sentence case is a brand decision more than a grammar one. Most modern publications (Vox, The Verge, New York Times article body) use Sentence case for clean, scannable reading. Traditional publishing (book covers, academic papers, legal briefs) sticks with Title Case for formal weight. Pick one and apply it consistently across headlines, subheadings, navigation, and CTAs.
Social posts
aLtErNaTiNg case (also called mocking SpongeBob case) signals sarcasm. UPPER CASE for whole sentences reads as shouting. iNVERSE cASE is a novelty effect, useful for memes and rare aesthetic posts. None of these convert well to accessibility software, so use sparingly on professional posts.
Frequently asked questions
Which case style should I use for headlines?
Use Title Case for headlines if your publication or brand style guide says so (most newspapers, books, and academic journals do). Use Sentence case if you want a cleaner, more conversational feel (most modern digital publications do). The case converter handles both, and the Title Case ruleset dropdown lets you pick AP, APA, MLA, Chicago, or NY Times conventions.
Is Title Case case-sensitive?
Yes, but the input does not need to be. The converter normalizes every word before applying the title-case rule, so "HELLO world", "hello WORLD", and "Hello World" all convert to the same output. Acronyms (NASA, USA, FBI) are preserved by default if they are typed in all caps in the input.
How does this handle apostrophes and hyphens?
Apostrophes inside a word (don't, can't, it's) stay where they are; the letter after the apostrophe stays lowercase (so "don't" in Title Case becomes "Don't", not "Don'T"). Hyphenated words capitalize each part in Title Case ("Mother-in-Law", "Twenty-One") under most style guides; the converter does the same.
Does the case converter support non-English titles?
The conversion is Unicode-safe, so accented characters (á, ü, ñ), Cyrillic, Greek, and other scripts case-convert correctly. The Title Case style rules (preposition lists, conjunction handling) are English-language rules, so they will not apply correctly to Spanish, French, or German titles. For non-English titles, use UPPER, lower, or Sentence case modes, which are language-neutral.
What is the difference between camelCase and PascalCase?
Both compress multi-word identifiers into one continuous string with no spaces. camelCase keeps the first character lowercase (theQuickBrownFox); PascalCase capitalizes the first character too (TheQuickBrownFox). The rule of thumb: camelCase for variables and functions, PascalCase for classes, types, and components.
Why does snake_case differ from CONSTANT_CASE?
snake_case is all lowercase with underscores (the_quick_brown_fox). CONSTANT_CASE is all uppercase with underscores (THE_QUICK_BROWN_FOX). Python uses snake_case for variable and function names, CONSTANT_CASE for module-level constants. The convention exists so readers can tell at a glance whether an identifier is meant to be reassigned (snake_case) or treated as a fixed value (CONSTANT_CASE).
Does the converter handle pasted Microsoft Word content?
Yes. Pasted content from Word, Google Docs, or other rich-text editors usually carries hidden characters (smart quotes, non-breaking spaces, formatting markers). The converter strips those before applying case rules, so the output is plain text safe to paste into a code editor, terminal, or URL. If you need the cleaning step on its own, see the Text Cleaner.
Is the case converter free?
Yes. No signup, no paywall, no character cap on input. Conversion runs entirely in your browser; the text never gets sent anywhere. Your draft is saved to local browser storage so coming back to the page keeps your work.
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