Case Converter Online — Upper, Lower, Title Case, Free

One text box, ten letter cases

Paste or type into the box and the case converter rewrites your text in place — UPPERCASE, lowercase, Sentence case, Title Case, camelCase, PascalCase, snake_case, kebab-case, plus two novelty styles (iNVERSE cASE and aLtErNaTiNg cAsE). A live counter under the box tracks characters and words as you edit, and one click copies the result to your clipboard. Every transformation runs in your browser, so nothing you paste is uploaded, there’s no length limit, and this stays a fast, free, online text transformer for developers, writers, and content creators alike.

Reach for it to fix a stuck Caps Lock line, generate a camelCase variable name, turn a heading into a clean kebab-case URL slug, or standardise a batch of titles before you drop them into the Word Counter or encode them with the URL Encoder.

What each button produces

Starting from the phrase Hello World, here is exactly what every button on the tool outputs and where that style is normally used:

Naming conventions by language

Which case a name uses is a convention, not a syntax rule — but following the convention is what makes code read as idiomatic to the next person on the team. These are the dominant styles for each kind of identifier across common languages, drawn from each ecosystem’s widely-followed style guides:

The same three identifiers, written idiomatically in three languages:

// JavaScript / TypeScript
let maxRetryCount = 3;               // camelCase variable
class HttpClient {}                  // PascalCase class
const API_BASE_URL = "api.site.com"; // UPPER_SNAKE_CASE constant

# Python (PEP 8)
max_retry_count = 3                  # snake_case variable
class HttpClient: ...                # PascalCase class
API_BASE_URL = "api.site.com"        # UPPER_SNAKE_CASE constant

// Rust
let max_retry_count = 3;             // snake_case
struct HttpClient;                   // PascalCase
const API_BASE_URL: &str = "...";    // SCREAMING_SNAKE_CASE

Title Case vs Sentence case — and where this tool draws the line

These two trip people up because they sound alike. Sentence case capitalises only the first letter of each sentence, the way you write ordinary prose. Title Case capitalises the first letter of every word, the way headlines are set. Same input, two different results:

Input:          the HTTP request reached NASA
Sentence case:  The http request reached nasa
Title Case:     The Http Request Reached Nasa

Two honest caveats about how these buttons behave here. Both first fold the whole string to lowercase and then re-capitalise, so any capital already inside a word is lost: NASA becomes Nasa, and iPhone becomes Iphone. And the Title Case button capitalises every word, including short ones — it does not apply the editorial rules (APA, Chicago) that keep articles and prepositions such as of, the, and to lowercase. If you want “The Lord of the Rings” rather than “The Lord Of The Rings”, lowercase those small words by hand after converting.

Common gotchas — and how to avoid them

Title Case capitalised words I wanted lowercase

The button uses one simple rule — capitalise every space-separated word — so it can’t know your style guide. For strict headline case, lowercase the short connecting words yourself after converting.

An acronym or brand name lost its capitals

Sentence case and Title Case lowercase the whole string first, so NASA, PDF, and iPhone come back flattened. Every button transforms the entire box, not a highlighted selection, so there is no way to fix one token in place — retype those acronyms and brand names by hand after converting.

Punctuation vanished from PascalCase, snake_case, or kebab-case

PascalCase, snake_case, and kebab-case rebuild a clean identifier from the words they find and drop stray symbols in the process — that is by design. camelCase is the exception: it only strips spaces, hyphens, and underscores, so other punctuation such as commas, dots, and slashes stays in its output. Feed the identifier styles the plain words you want in the name and keep punctuation out.

Nothing downloaded

There is no file to download — the tool rewrites the text inside the box. Use the Copy button to grab the result, or the clear button to empty the box and start again.

Alternating case looks misaligned

aLtErNaTiNg cAsE flips by character position and counts spaces in that count, so the up-down rhythm is positional across the whole string, not strictly per visible letter.

Frequently asked questions