Text Case Converter

Converting text case with Thetoolity is immediate.

Step 1: Paste or type your text into the input field. You can paste any amount of text regardless of its current case.

Step 2: Click the case format button you need. The converted text appears instantly in the output area.

Step 3: Copy your result. Click the copy button to copy the converted text to your clipboard and paste it wherever you need it.

Every conversion is instant. There is no need to click a separate convert button after selecting your case type.

Thetoolity's case converter supports the most widely used text case formats across writing, publishing, and programming. Here is what each one does and when to use it.

UPPERCASE

Uppercase converts every letter in the text to its capital form. Punctuation and numbers are unchanged.

Example input: The quick brown fox jumps over the lazy dog. Example output: THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG.

When to use it: UPPERCASE is used for acronyms, abbreviations, labels, headers, legal notices, and anywhere strong visual emphasis or formal notation is required. It is also the standard for constants in most programming languages (MAX_VALUE, DEFAULT_TIMEOUT, API_KEY).

lowercase

Lowercase converts every letter to its small form. Punctuation and numbers are unchanged.

Example input: THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG. Example output: the quick brown fox jumps over the lazy dog.

When to use it: Lowercase is the most common use case for this tool. Writers who accidentally typed with Caps Lock on use it to fix their text instantly. It is also used for converting text before applying another case format, for programming identifiers in languages that use all lowercase, and for username and slug normalization.

Title Case

Title Case capitalizes the first letter of each significant word while leaving minor words like articles, prepositions, and conjunctions in lowercase.

Example input: the quick brown fox jumps over the lazy dog Example output: The Quick Brown Fox Jumps Over the Lazy Dog

When to use it: Title Case is used for book titles, article headlines, movie titles, song names, chapter headings, and any formal heading in a document. The exact rules for which words should be capitalized vary by style guide. The Chicago Manual of Style, APA style, and AP style each have slightly different rules for title case. Most title case converters follow the widely accepted convention of capitalizing all major words (nouns, verbs, adjectives, adverbs) and leaving minor words (a, an, the, and, but, or, for, in, on, at, to) lowercase unless they are the first or last word.

Sentence Case

Sentence Case capitalizes only the first letter of each sentence and leaves everything else lowercase. Proper nouns and the pronoun I are also capitalized.

Example input: the quick brown fox. the lazy dog sleeps. Example output: The quick brown fox. The lazy dog sleeps.

When to use it: Sentence case matches natural written prose. It is the correct format for body text in documents, emails, descriptions, and any writing that follows standard grammatical capitalization. It is also widely used for subheadings in blog posts, product descriptions, and UI text where title case would feel overly formal.

Capitalized Case

Capitalized Case (also called Word Case) capitalizes the first letter of every single word, including minor words like "and," "the," and "of."

Example input: the quick brown fox jumps over the lazy dog Example output: The Quick Brown Fox Jumps Over The Lazy Dog

When to use it: Capitalized Case is sometimes used for proper names, brand names, navigational elements, and contexts where every word should be visually treated as equally important. It is a simpler variant of Title Case that applies the same rule to every word without exception.

camelCase

camelCase removes spaces and capitalizes the first letter of each word except the first, which stays lowercase. No separators are used between words.

Example input: the quick brown fox Example output: theQuickBrownFox

When to use it: camelCase is the dominant naming convention for variables and functions in JavaScript, Java, Swift, Kotlin, and many other programming languages. When you create a variable in JavaScript, the convention is camelCase: userFirstName, totalOrderCount, isLoggedIn. JSON keys frequently use camelCase. API response fields from most modern REST APIs use camelCase.

PascalCase

PascalCase is the same as camelCase but the first letter of the first word is also capitalized. It is also called UpperCamelCase.

Example input: the quick brown fox Example output: TheQuickBrownFox

When to use it: PascalCase is the convention for class names and component names in most object-oriented and component-based programming. React component names must be PascalCase (UserProfile, ShoppingCart, NavBar). Class names in Java, C#, Python, and Swift use PascalCase. TypeScript interface and type names also conventionally use PascalCase.

snake_case

snake_case replaces spaces with underscores and converts all letters to lowercase.

Example input: the quick brown fox Example output: the_quick_brown_fox

When to use it: snake_case is the primary naming convention in Python for variables, functions, and module names. It is also used in Ruby, PHP, and many database column names. SQL databases commonly use snake_case for table and column names. File names in many frameworks and systems use snake_case for multi-word filenames.

kebab-case

kebab-case replaces spaces with hyphens and converts all letters to lowercase.

Example input: the quick brown fox Example output: the-quick-brown-fox

When to use it: kebab-case is used extensively in web development for URL slugs, HTML attribute values, CSS class names, file names, and command-line arguments. CSS class naming conventions like BEM (Block Element Modifier) use kebab-case. URL-friendly slugs for blog posts and pages use kebab-case. HTML data attributes use kebab-case. npm package names typically use kebab-case.

Alternating Case

Alternating Case switches between uppercase and lowercase letters for each successive character.

Example input: the quick brown fox Example output: tHe QuIcK BrOwN FoX

When to use it: Alternating case is primarily used for ironic or sarcastic effect in online communication, often called "mock" or "spongebob" case. It is used in meme culture and social media to convey mockery or disbelief. It has no formal writing or programming application.

Inverse Case

Inverse Case flips the case of every letter. Uppercase letters become lowercase and lowercase letters become uppercase.

Example input: The Quick Brown Fox Example output: tHE qUICK bROWN fOX

When to use it: Inverse case is useful for quickly fixing text that was typed with Caps Lock accidentally engaged in the middle of a document. It is also used as a stylistic effect and for creative text purposes.

Text case conventions in programming are not aesthetic preferences. They are enforced standards that affect code readability, consistency, and in some cases whether code compiles or runs correctly. Here is a complete guide to which case convention applies in which context.

JavaScript and TypeScript

Variables and function names use camelCase: const firstName, function getUserData(). Class and interface names use PascalCase: class UserService, interface ApiResponse. Constants use SCREAMING_SNAKE_CASE (all uppercase with underscores): const MAX_RETRIES, const DEFAULT_TIMEOUT. React component names must be PascalCase or they will not render correctly: const UserProfile, const NavigationBar.

Python

Variables, functions, and module names use snake_case: user_first_name, calculate_total(), import my_module. Class names use PascalCase: class UserAccount. Constants use SCREAMING_SNAKE_CASE: MAX_CONNECTIONS, API_BASE_URL. Package names use all lowercase with no separators when possible.

Java and Kotlin

Variables and method names use camelCase: int userAge, void getUserById(). Class names use PascalCase: class OrderService. Constants (static final fields) use SCREAMING_SNAKE_CASE: MAX_QUEUE_SIZE. Package names use all lowercase with dot separators: com.example.myapp.

C# and .NET

Public properties, methods, and classes use PascalCase: public string FirstName, public void ProcessOrder(). Private fields use camelCase or underscore-prefixed camelCase: private string _userId. Constants and enums use PascalCase. Local variables use camelCase.

CSS and HTML

CSS class names conventionally use kebab-case: .button-primary, .nav-container, .hero-section. HTML attribute names use kebab-case: data-user-id, aria-label. CSS custom properties (variables) use two hyphens and kebab-case: --primary-color, --font-size-base.

Database (SQL)

Column and table names typically use snake_case in most databases: user_id, first_name, created_at, order_total. Some databases and ORMs use camelCase for programmatic access while the underlying column uses snake_case.

File naming

Web project files typically use kebab-case: user-profile.html, main-navigation.css. Python files use snake_case: user_service.py, data_parser.py. JavaScript and TypeScript files vary by convention: some teams use camelCase (userService.js) and others use kebab-case (user-service.js). React component files typically use PascalCase to match the component name: UserProfile.jsx.

Command-line tools and CLI arguments

Command-line flags and arguments use kebab-case: npm install, git commit, kubectl apply. Long-form arguments use two hyphens: git commit, then the flag name in kebab-case.

Title case seems straightforward but the specific rules for which words to capitalize vary significantly between style guides. If you are writing for a specific publication, academic institution, or content platform, knowing which guide they follow helps you apply the correct title case format.

Chicago Manual of Style (CMOS)

The Chicago Manual of Style is the most widely used style guide for book publishing and long-form writing in the United States. Its title case rules capitalize all words except articles (a, an, the), coordinating conjunctions (and, but, for, or, nor, so, yet), and prepositions (in, on, at, to, for, by, with, from) unless they are the first or last word of the title. Phrasal verbs like "Look Up" capitalize both words.

APA Style (American Psychological Association)

APA title case capitalizes all words of four letters or more, all verbs and nouns regardless of length, and the first word after a colon or dash. Words of three letters or fewer that are not verbs or nouns are lowercased. APA is common in academic writing, particularly in psychology, social sciences, and education.

AP Style (Associated Press)

AP style, used by most newspapers and news organizations, capitalizes all words of four letters or more. Shorter words that are verbs, nouns, pronouns, adjectives, or adverbs are also capitalized. Articles, conjunctions, and short prepositions remain lowercase unless they are the first word.

MLA Style (Modern Language Association)

MLA capitalizes the first and last words of a title and all major words. Prepositions, conjunctions, and articles are lowercase unless they are the first word. MLA is common in humanities scholarship and literary writing.

For most everyday purposes and digital content creation, using a title case converter that follows the Chicago Manual of Style conventions produces the most widely accepted result.

These are the text case errors that appear most frequently in professional writing and content work, along with the fix for each one.

• ALL CAPS text that should be normal prose. This happens when someone types an email or document with Caps Lock accidentally engaged. The fix: paste the text into Thetoolity's converter and click lowercase. If the text needs proper sentence capitalization, follow with sentence case.

• First word not capitalized after a sentence. When copying text from code comments, terminal output, or database fields, text often comes through in all lowercase with no sentence capitalization. The fix: use sentence case to restore proper capitalization at the start of each sentence.

• Headline in sentence case when it should be title case. Blog post titles, article headlines, and chapter headings formatted as plain sentence case look informal. The fix: run the title through the title case converter.

• Variable name with spaces. When a designer writes a component name or a spreadsheet has column headers that need to become variable names, spaces cause errors. The fix: use camelCase or snake_case conversion to produce a valid identifier.

• Database column names in mixed case. SQL and most databases are case-insensitive for identifiers, but convention and readability demand consistent case. snake_case is the standard for most databases. The fix: convert any column names that are in mixed case to snake_case.

• CSS class names from copied content. Content copied from a design tool or documentation may have class names in PascalCase or camelCase, while CSS convention requires kebab-case. The fix: convert to kebab-case.

Some words have established casing that falls outside normal grammar rules and should not be changed by a case converter regardless of the context.

Technology companies and products commonly use unconventional casing as part of their brand identity. iPhone begins with a lowercase i regardless of position. iPad, iPod, iMac, and other Apple products follow the same pattern. eBay begins with a lowercase e even at the start of a sentence. GitHub uses a capital G and capital H in the middle of the word. YouTube capitalizes both T and Y. WordPress capitalizes P in the middle of the word. JavaScript capitalizes S in the middle. LinkedIn capitalizes both L and I.

When running brand names through a case converter, be aware that the output may not match the brand's official casing. The result from a case converter treats text mechanically and cannot distinguish brand names from common words. Always review converted text for proper noun capitalization before finalizing.

If you regularly need to change text case inside a specific application, built-in features can be faster than using an online converter for small tasks.

• Microsoft Word: Select the text, then use Format, Text Effects and Typography or press Shift+F3 to cycle through lowercase, UPPERCASE, and Title Case options. The Change Case option in the Home tab provides a full dropdown with all case options.

• Google Docs: Select the text, go to Format, then Text, then Capitalization. Options include lowercase, UPPERCASE, and Title Case. Google Docs does not have built-in sentence case conversion.

• Microsoft Excel: The UPPER(), LOWER(), and PROPER() functions convert text in cells. UPPER("hello") returns "HELLO". LOWER("HELLO") returns "hello". PROPER("hello world") returns "Hello World".

• Google Sheets: The same UPPER(), LOWER(), and PROPER() functions are available.

• VS Code (code editor): Select text, open the Command Palette with Ctrl+Shift+P, and search for "Transform to Uppercase," "Transform to Lowercase," or install the "Change Case" extension for additional formats including camelCase, snake_case, and kebab-case.

For bulk conversion of larger text blocks or specialized case formats not available in these applications, Thetoolity's online converter is the fastest solution.

Thetoolity is a growing collection of free, fast, and clean online tools for writers, developers, students, and anyone who works with text every day. Our text case converter is one of many tools designed to handle everyday text formatting tasks instantly, with no account required and no data leaving your device.

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