Case Converter

What is a case converter?

A case converter is a tool that changes the letter casing of a piece of text — for example, turning "hello world" into "Hello World" (Title Case), "HELLO WORLD" (UPPERCASE) or "hello world" (lowercase). Letter casing is one of the most basic typographic conventions in written English and most other Latin-alphabet languages, and choosing the right case matters for readability, style, programming conventions and search engine optimisation.

Beyond the basic UPPERCASE, lowercase, Title Case and Sentence case transformations, a good case converter also handles the programming-style conventions that developers use every day: camelCase (used by JavaScript, Java and Swift), snake_case (used by Python, Ruby and Rust), kebab-case (used by CSS, URLs and HTML attributes) and CONSTANT_CASE (used for environment variables and constants). This tool supports all eight common conventions in a single click.

Case conventions compared

Different case conventions exist because different communities adopted different rules over time. The table below summarises the most common ones and where you typically find them:

Case	Example	Typical use
UPPERCASE	HELLO WORLD	Headlines, warnings, emphasis
lowercase	hello world	Casual writing, code comments
Title Case	Hello World	Book titles, headings
Sentence case	Hello world	Sentences, captions, buttons
camelCase	helloWorld	JavaScript, Java variables
snake_case	hello_world	Python, Ruby, Rust
kebab-case	hello-world	CSS classes, URLs, HTML attrs
CONSTANT_CASE	HELLO_WORLD	Constants, env variables

Choosing the right convention makes your code, content and identifiers consistent with the surrounding ecosystem, which improves readability and avoids linting errors.

When to use a case converter

There are many practical situations where a quick case converter saves time. The most common ones include:

• Rewriting headings and titles. Quickly capitalise a heading for a blog post, slide or document without retyping every word.
• Fixing all-caps text. Turn text pasted from a PDF, banner or screenshot that came in as ALL CAPS into normal sentence text.
• Rename code identifiers. Convert a Python snake_case variable to camelCase when porting code to JavaScript, or vice versa.
• Build CSS class names and URLs. Convert a feature name into a kebab-case CSS class or URL slug in one click.
• Normalise form input. Standardise user-provided text (email, postcode, product code) before validation or storage.
• Create constants and env variables. Turn a config key into CONSTANT_CASE for use in .env files or language constants.

Wherever you need to switch a piece of text from one convention to another, a case converter is the fastest way to do it accurately.

How to convert case

Converting the case of your text with this tool takes only a second and happens entirely inside your browser. No upload, no sign-up, and no installation are required. Follow these three steps:

1. Paste your text. Click inside the input box on the left and paste or type the text you want to convert.
2. Pick a conversion type. Click one of the eight buttons on the right — UPPERCASE, lowercase, Title Case, Sentence case, camelCase, snake_case, kebab-case or CONSTANT_CASE.
3. Copy the result. The converted text appears in the result box. Click "Copy result" to copy it to your clipboard, or "Clear" to start over.

Because every conversion is computed locally with JavaScript on your own device, your text never leaves your browser. This makes the tool completely private and suitable for confidential drafts, source code and unpublished content.

Tips for choosing the right case

Picking the right case is partly a question of style and partly a question of convention. For prose, use Sentence case for body text, captions and buttons because it is easier to read, and reserve Title Case for short headings and titles where each word stands out. Avoid ALL CAPS for long passages because it slows readers down by removing the visual shape of words.

For code, follow the convention of the language and project you are working in: camelCase for JavaScript variables and functions, PascalCase for JavaScript classes and React components, snake_case for Python and Ruby identifiers, kebab-case for CSS classes and URLs, and CONSTANT_CASE for constants and environment variables. Sticking to the project's existing convention is usually more important than picking the "perfect" case — consistency wins.