Case Converter
100% private — runs on your device, never uploaded. Works offline once loaded.
Instantly convert your text between UPPERCASE, lowercase, Title Case, Sentence case, camelCase, snake_case and kebab-case. Everything runs locally in your browser.
The seven cases and where each one belongs
Each case format exists because a specific context expects it. camelCase (firstName) is the variable-naming convention in JavaScript, Java and Swift; PascalCase (FirstName) is used for class and component names in the same languages; snake_case (first_name) is standard for variables in Python and for column names in SQL databases; and kebab-case (first-name) is required for CSS class names and is the convention for URL slugs because browsers and search engines treat hyphens as word separators.
- UPPERCASE — acronyms, constants, shouting emphasis
- lowercase — normalizing messy input, file names, tags
- Title Case — headlines, book and article titles
- Sentence case — cleaning up text typed in all caps
- camelCase / PascalCase — code variables and class names
- snake_case — Python, SQL, config keys
- kebab-case — CSS classes, URL slugs
Everyday situations this solves
A common one: someone emails you a spreadsheet with column headers typed in ALL CAPS by an old export script, and you need them as clean snake_case before importing into a database. Another: you're porting a Python script's variable names to JavaScript and need first_name to become firstName without retyping every line by hand. Writers and editors reach for Title Case to match a publication's headline style guide, and marketers use kebab-case to turn a blog post title into a clean, readable URL slug.
Where the logic gets tricky
Title Case isn't as simple as capitalizing every word — most style guides (AP, Chicago) keep short articles, conjunctions and prepositions like "a", "the", "of" and "and" lowercase unless they start the title, though implementations vary and this tool applies a simple capitalize-every-word rule, so you may want to manually lowercase small words afterward for strict editorial style. When converting to camelCase or snake_case, spaces, hyphens and underscores are all treated as word boundaries, so "user-id" and "user id" both convert the same way.
A tip for developers
If you're renaming a batch of API field names or config keys, convert the whole block at once rather than word by word — paste the full JSON or CSV column list in, convert, and paste it back to save yourself dozens of manual edits.
Frequently asked questions
Is my text uploaded?
No — the conversion happens on your device and your text stays private.
What is Title Case?
Title Case capitalises the first letter of each word, like a headline.
Does Title Case correctly lowercase words like "the" or "of"?
This tool capitalizes every word for simplicity; strict editorial style guides like AP or Chicago keep short articles and prepositions lowercase mid-title, so for formal headlines you may want to manually adjust a few small words after converting.
What's the actual difference between camelCase and PascalCase?
Both remove spaces and capitalize word boundaries — camelCase starts with a lowercase letter (firstName) and is used for variables, while PascalCase starts with an uppercase letter (FirstName) and is used for class or component names.
Will it handle accented characters like é or ñ correctly?
Yes, uppercase and lowercase conversion works correctly with accented Latin characters, though some very locale-specific rules (like Turkish dotless ı) may not be preserved exactly.
Does it know the difference between an acronym and a regular word?
No — a word like "NASA" typed in a sentence will be converted along with everything else in lowercase or Title Case, so acronyms you want preserved as-is should be fixed manually after conversion.
When should I use snake_case instead of kebab-case?
Use snake_case for Python variables, database columns and most config file keys; use kebab-case for CSS class names and URL slugs, since hyphens (not underscores) are what search engines treat as word separators in URLs.
Does converting case change my line breaks or spacing?
Line breaks and paragraph spacing are preserved for the space-separated cases (UPPERCASE, lowercase, Title Case, Sentence case); camelCase, snake_case and kebab-case necessarily collapse spacing since those formats don't use spaces.
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