Free Case Converter — UPPERCASE, camelCase, snake_case & More

How to Convert Text Case Online

Converting text with Pixab AI's case converter is instant and requires no account or software installation. Start by typing directly into the text box above or pasting your content with Ctrl+V (Cmd+V on Mac). The word and character counters beneath the editor update in real time so you always know the size of your input.

Once your text is in the editor, click any of the twelve conversion buttons — UPPERCASE, lowercase, Title Case, Sentence case, camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE, dot.case, aLtErNaTiNg, and InVeRsE CaSe. The result appears immediately in the output panel below the buttons. The active button stays highlighted in indigo so you can see at a glance which conversion you last applied.

To copy the result to your clipboard, click the Copy button in the output panel. It will briefly show a green “Copied!” confirmation so you know the copy succeeded. You can then paste the converted text anywhere — a code editor, a word processor, a browser address bar, or a spreadsheet.

If you need to convert text from a plain-text file, click the Upload .txt button. The file is read entirely in your browser using the FileReader API — nothing is uploaded to any server. After uploading, the active conversion (if you already clicked a button) runs automatically on the new content. You can then switch between conversions as many times as you like using the same input.

To start over, click Clear to empty the input and reset the output. The tool supports text of any length — from a single variable name to a full article. For further text processing, use our URL Slug Generator to turn your converted text into a clean URL slug, or the Word Counter for a full text analysis.

When to Use Each Text Case

UPPERCASE — Emphasis and Acronyms

All-caps text is rarely appropriate for long passages because it slows reading speed and feels aggressive in digital communication. Its legitimate uses are narrow but important: acronyms and initialisms (NASA, HTML, PDF), strong emphasis in headings, warning labels (CAUTION, WARNING), and all-caps variable names in certain programming styles. In spreadsheets and database exports, values often arrive in uppercase and need to be normalised before display.

lowercase — Clean Formatting and Code

Lowercase is the default for body text, email addresses, domain names, and most programming keywords. It is also the starting point for constructing any other case format — you typically lowercase first, then re-capitalise as needed. When text is copied from PDFs, legacy systems, or old databases, it frequently arrives in mixed or broken case; converting everything to lowercase first is a reliable way to normalise it before reformatting.

Title Case — Headings and Book Titles

Title case capitalises the first letter of most words but keeps short function words like “a,” “an,” “the,” “and,” “but,” and “or” in lowercase (unless they appear as the first or last word). It is the standard for book titles, film titles, article headings, album names, and product names. Our case converter implements a rule set that matches the Chicago Manual of Style approach, skipping 17 common function words including prepositions (on, at, in, by, to, up, of) and conjunctions. Use title case for H1 and H2 headings in marketing copy, press releases, and SEO page titles.

Sentence case — Body Text and Subtitles

Sentence case capitalises the first letter of the first word in each sentence and after sentence-ending punctuation (. ! ?) but leaves all other words lowercase (except proper nouns, which the tool preserves). It is the natural format for body paragraphs, subtitles, UI error messages, and tooltip text. Many style guides — including Google's Material Design guidelines — recommend sentence case over title case for button labels and interface text because it reads more conversationally.

camelCase — JavaScript, TypeScript, and JSON

camelCase concatenates words with no separator and capitalises the first letter of every word after the first. It is the dominant convention for variable names, function names, and object property keys in JavaScript and TypeScript (getUserById, isLoggedIn, pageTitle). JSON keys also conventionally use camelCase in APIs that follow JavaScript naming conventions. When you copy a column header from a spreadsheet like “First Name” and need a matching JavaScript variable, our tool converts it to firstName in one click.

PascalCase — Classes and React Components

PascalCase is identical to camelCase except the very first letter is also capitalised. It is the universal convention for class names in object-oriented languages (Java, C#, TypeScript) and for React component names (UserProfile, NavigationBar, PricingTable). In C# and .NET, PascalCase is also used for public methods and properties. If you are scaffolding a new component and have a description like “user profile card,” converting to PascalCase gives you the correct filename and import name immediately.

snake_case — Python, Databases, and Ruby

snake_case separates words with underscores and keeps everything lowercase. It is the standard naming convention in Python (PEP 8: get_user_by_id, is_admin), PostgreSQL and MySQL table and column names (user_profiles, created_at), Ruby on Rails, and many configuration file keys. When you export data from a CSV or copy field names from a form, converting them to snake_case gives you database-ready column names without any manual editing.

kebab-case — URLs, CSS, and HTML

kebab-case uses hyphens instead of underscores and keeps everything lowercase. It is the standard for URL slugs (/tools/case-converter), HTML element IDs (id="main-content"), CSS class names (.nav-item), and HTML data attributes (data-user-id). Search engines treat hyphens as word separators in URLs, making kebab-case slugs inherently more SEO-friendly than underscore slugs. Our URL Slug Generator is a dedicated tool for this conversion with additional features like special-character handling and Unicode support.

CONSTANT_CASE — Environment Variables and Config

CONSTANT_CASE is uppercase snake_case. It signals that a value should not change at runtime. It is universally used for environment variables (DATABASE_URL, API_SECRET_KEY), constants in JavaScript/TypeScript (MAX_RETRY_COUNT), and configuration keys in .env files. When setting up a new project and listing required environment variables, converting human-readable names to CONSTANT_CASE is one of the first formatting tasks.

dot.case — Configuration and Package Names

dot.case separates words with periods. It appears in Java package names (com.company.feature), some configuration file keys, and logging namespaces. It is less common than other formats but useful when working with hierarchical identifiers where dots denote hierarchy levels.

aLtErNaTiNg cAsE — Memes and Creative Use

Alternating case flips each letter between lowercase and uppercase in a strict pattern, starting with lowercase. It originated in internet culture as a way to mock or sarcastically echo a statement and appears heavily in meme formats like “SpOnGeBoB mocking meme.” Outside of humour, it has minimal practical use, but it is genuinely useful for quickly generating the format for creative social media posts or testing how a UI handles unusual capitalisation patterns.

InVeRsE CaSe — Flipping Existing Capitalisation

Inverse case swaps each character individually: uppercase letters become lowercase, and lowercase letters become uppercase. Unlike alternating case, it respects the original pattern of the text. If you type “Hello World” the inverse is “hELLO wORLD.” This is useful for testing rendering systems, generating visual contrast in creative designs, or simply having fun with text transformation.

Title Case Rules: Chicago vs AP vs APA Style

Title case is not a single standard — it varies by style guide, and the differences are subtle but matter for professional writing.

The Chicago Manual of Style (the most widely used standard in publishing) lowercases articles (a, an, the), coordinating conjunctions (and, but, or, for, nor), and prepositions of any length (in, on, at, by, to, up, of, with, between, through) unless they appear as the first or last word. The title of a book like “The Old Man and the Sea” follows Chicago rules exactly.

The AP Stylebook (used by journalists and news organisations) lowercases prepositions of three letters or fewer but capitalises longer prepositions like “With,” “Through,” and “Between.” It also capitalises “Is” because “is” is a verb, not a conjunction or preposition.

The APA Manual (used in academic psychology and social sciences) capitalises any word of four or more letters, regardless of part of speech. It also capitalises the first word after a colon in a title.

Our case converter follows a conservative rule set close to Chicago style, which is the most broadly applicable. For AP or APA compliance, use the output as a starting point and manually adjust the edge cases — they are typically just one or two words per title. For further formatting, our Find & Replace tool lets you make targeted corrections across large batches of text.

Programming Naming Conventions

Every major programming language has a dominant naming convention, and mixing conventions within a codebase is a common source of code review friction. Understanding which case to use in which language removes that friction:

JavaScript and TypeScript: camelCase for variables and functions; PascalCase for classes, interfaces, type aliases, and React components; CONSTANT_CASE for top-level constants and environment variables. CSS class names in component-scoped CSS still use kebab-case.

Python: snake_case for variables, functions, and module names (PEP 8); PascalCase for class names; CONSTANT_CASE for module-level constants. Python is notably strict — the community strongly enforces PEP 8 via linters like flake8 and black.

SQL: snake_case is the dominant convention for table names, column names, and stored procedure names across PostgreSQL, MySQL, and SQLite. Some shops use UPPERCASE for SQL keywords (SELECT, FROM, WHERE) for readability, though most modern formatters handle this automatically.

Java and C#: PascalCase for classes, interfaces, enums, and public methods; camelCase for local variables and parameters; CONSTANT_CASE for static final constants. C# adds an “I” prefix convention for interfaces (IDisposable, IEnumerable).

Go: PascalCase for exported (public) identifiers; camelCase for unexported (private) ones. Go has no constants keyword in the traditional sense, but community convention uses PascalCase for exported constants.

CSS and HTML: kebab-case for class names, IDs, and custom property names (--color-primary). BEM methodology extends this: block__element--modifier.

Common Use Cases for a Case Converter

Cleaning up text copied from PDFs. PDFs frequently store text with broken capitalisation — headers may appear in ALL CAPS due to CSS styling that is lost on copy, or body text may come through with random mid-word capitals from the underlying font encoding. Converting to lowercase and then to the desired case is the fastest way to recover clean text.

Formatting spreadsheet data. Column headers exported from databases or legacy ERP systems often arrive in SCREAMING_SNAKE_CASE or ALL CAPS. Converting them to Title Case for a presentation or to camelCase for a JSON export is a task that comes up constantly in data work.

Code refactoring. When renaming variables across a codebase — for example, changing a Python function to a JavaScript function — you need to convert snake_case names to camelCase quickly. Pasting the list of names, converting, and copying back removes manual error.

Writing consistent headings. Blog posts and documentation files often end up with inconsistent heading capitalisation after multiple contributors edit them. Pasting all headings at once and running Title Case or Sentence Case normalises them immediately.

Generating URL slugs. Before using our dedicated URL Slug Generator, converting a blog title to lowercase is a useful first step. The slug generator then handles special characters, accents, and spaces.

Creating env variable names. When documenting a new feature's required environment variables, developers often start with a descriptive English phrase and need it in CONSTANT_CASE for the .env file. One click converts the phrase into the correct format.

Frequently Asked Questions

Does the case converter work on any language?

The converter works on any Latin-script text and handles Unicode characters correctly for the most common conversions (UPPERCASE, lowercase, Sentence case). For camelCase, PascalCase, snake_case, and similar formats that split on word boundaries, the tool splits on spaces, hyphens, and underscores — which works for any language that uses these separators. Languages that do not use spaces between words (Chinese, Japanese, Thai) will not split correctly for those formats.

Does Title Case capitalise every word?

No. Our Title Case follows Chicago Manual of Style rules. It lowercases articles (a, an, the), coordinating conjunctions (and, but, or, for, nor), and most prepositions (on, at, to, by, in, up, as, of, is) unless they are the first or last word in the title. Every other word is capitalised.

Why does Sentence case not capitalise proper nouns?

Detecting proper nouns automatically requires a named-entity recognition system, which is beyond the scope of a browser-based text tool. Sentence case capitalises only the first letter of each sentence and the first letter of the overall text. Proper nouns that were already capitalised in the input will be correctly preserved because Sentence case only lowercases everything first and then re-capitalises sentence starts — it does not touch mid-sentence uppercase letters.

Can I convert a whole document at once?

Yes. Use the Upload .txt button to load a plain-text file. There is no enforced size limit — the tool handles documents in your browser's available memory, which is typically several hundred megabytes for modern browsers. For very large documents (full book manuscripts), conversions may take a fraction of a second longer than usual.

Does camelCase remove spaces?

Yes. camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE, and dot.case all remove spaces (replacing them with the appropriate separator or no separator). This is intentional — these formats are used in code and URLs where spaces are not allowed. If you need to preserve spaces, use UPPERCASE, lowercase, Title Case, Sentence case, aLtErNaTiNg, or InVeRsE CaSe.

What happens to special characters and numbers?

Numbers are preserved in all conversions. Special characters (punctuation, symbols) are also preserved except in camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE, and dot.case, which split on hyphens and underscores in addition to spaces. Punctuation within words (like apostrophes in contractions) is preserved.

Is my text sent to any server?

No. All twelve conversions run entirely in your browser using JavaScript. Your text is never transmitted to any server. This makes the tool safe for confidential content like internal documents, proprietary code, or personal notes. You can even use it offline once the page has loaded — disconnect from Wi-Fi and the conversions will still work.