Free Online Case Converter - UPPER, lower, Title, Sentence & More

The Delimiter.site Case Converter transforms any text into six different capitalisation styles instantly - no typing, no formulas, no spreadsheet required. Paste your text, click the case you want, and copy the result in one click.

The Six Case Styles Explained

Each button applies a different transformation rule to every character in your text. Understanding what each style does helps you pick the right one the first time.

Sentence Case

Capitalises the first letter of every sentence and lowercases everything else. A sentence is detected after a full stop, exclamation mark, or question mark followed by whitespace. Example: "the quick BROWN fox. a lazy dog." → "The quick brown fox. A lazy dog."

Title Case

Capitalises the first letter of every significant word. Small function words - a, an, the, and, but, or, for, nor, on, at, to, by, in, of - are kept lowercase unless they appear at the start of the text. Example: "the art of war" → "The Art of War"

UPPER CASE

Converts every character to its uppercase equivalent using the browser's built-in toUpperCase() method, which correctly handles accented and non-Latin characters. Example: "Hello World" → "HELLO WORLD"

lower case

Converts every character to lowercase using toLowerCase(). Example: "Hello World" → "hello world"

Toggle Case

Inverts the case of every individual character - uppercase becomes lowercase and vice versa. Example: "Hello World" → "hELLO wORLD"

rAnDoM CaSe

Randomly assigns uppercase or lowercase to each character with equal probability. The result is different every time you click the button, making it useful for meme text, playful content, or visual randomness tests. Example: "hello world" → "hElLo WoRlD" (varies each time)

How to Use the Case Converter

Step 1 - Paste or Type Your Text

Click the Paste button to pull text directly from your clipboard, or type into the input panel on the left. The output updates automatically whenever you change the active case or modify your input.

Step 2 - Select a Case Style

Click any of the six case buttons on the right sidebar. The active case is highlighted and shown in the header bar. The output panel updates immediately.

Step 3 - Copy the Result

Click Copy output in the bottom bar, or the copy icon in the output panel header. A toast notification confirms the text is on your clipboard.

Step 4 - Clear and Convert Again

Press Clear to reset the input and deselect the active case, ready for your next conversion.

Common Use Cases

Fixing Accidentally Caps-Locked Text

If you typed a paragraph with Caps Lock on, paste the text and apply Sentence case or lower case to fix it instantly - far faster than retyping or manually selecting and re-casing words in a word processor.

Formatting Headlines and Titles

Blog posts, press releases, and book chapters often require Title Case headlines. Paste your working title and apply Title Case to get the correctly formatted version without memorising capitalisation rules.

Normalising User Input in Data Pipelines

Data collected from forms often has inconsistent casing - some users type in all caps, others in all lowercase. Apply lower case or Sentence case to normalise a batch of entries before loading them into a database.

Code Identifier Preparation

When converting display names to programming identifiers, lowercase is often the first step before applying further transformations such as replacing spaces with underscores or hyphens. Use the Case Converter for the first step, then the Slug Generator for the rest.

Which Case Should You Use?

Frequently Asked Questions

Which words stay lowercase in Title Case?

Style guides disagree: AP and Chicago lowercase short conjunctions and prepositions (a, an, the, of, in, on), while APA capitalises any word of four letters or more. Whichever guide you follow, always review short words after converting.

Will acronyms like NASA survive conversion?

Converting to lower or sentence case rewrites every letter, so acronyms become "nasa". Scan your text for acronyms and proper nouns after converting — that's the one thing no automatic converter can reliably know for you.

Can I convert text to camelCase or snake_case?

Those are identifier formats rather than sentence cases. Use the slug generator for hyphen- or underscore-separated output, or the text tool to chain replacements that build identifier names.

Does conversion change anything besides letters?

No — numbers, punctuation, spacing and line breaks all pass through untouched. Only the letters' capitalisation changes.

Is my text sent to a server?

No. Conversion is instant JavaScript in your browser; nothing is uploaded or stored.