8 case modes, live preview · Programmer cases included · Runs in your browser · no upload
What a case converter does (and which mode to pick)
Convert text between UPPERCASE, lowercase, Title Case, Sentence case, aLtErNaTiNg cAsE, camelCase, snake_case and kebab-case. Live preview as you type or switch modes. Everything runs in your browser; your text never leaves your device. Free, private, no sign-up.
Where a word counter measures length and a character counter tracks platform limits, a case converter rewrites the letters themselves. Two jobs sit under one tool: prose case transformations (UPPER, lower, Title, Sentence, alternating) and programmer-style identifier cases (camelCase, snake_case, kebab-case). The right pick depends on where the text is going, not on personal preference.
Five prose cases: UPPERCASE, lowercase, Title Case, Sentence case, aLtErNaTiNg cAsE
Three programmer cases: camelCase, snake_case, kebab-case for code, slugs, CSS classes
Live preview as you type or change the mode; nothing leaves your browser
Copy the converted text in one click; words and character counts shown alongside
Quick answer
Picking case is a destination question, not a style one. URL slug? kebab-case. Python variable? snake_case. Book title? Title Case. Headline you want to shout? UPPERCASE. Body copy on a modern website? Sentence case.
Case conversion cheat sheet
Same eight modes the live converter offers, with one shared example ("Hello world") so you can compare side by side. The Context column is where each case actually shows up in the wild.
Case
Example
Where you'll use it
UPPERCASE
HELLO WORLD
Strong emphasis, headlines, legal disclaimers, country / status codes.
lowercase
hello world
Casual or modern brand voice, hashtags, terminal commands, URLs.
Title Case
Hello World
Book / article / song titles. Major words capitalized; minor words (the, of, and) left lowercase in the middle.
Sentence case
Hello world
Body copy, UI text, headings in modern web style (Google, GitHub, GOV.UK).
aLtErNaTiNg
hElLo WoRlD
Meme / mocking tone. Useful as a visual demo of irony, never for serious writing.
camelCase
helloWorld
JavaScript / Java / Swift / Kotlin variables and methods; JSON object keys in JS APIs.
A small team of writers and engineers shipping privacy-first text tools. Title Case follows the AP / Chicago overlap (minor words like "of", "the", "and" stay lowercase in the middle); programmer cases follow the conventions used in mainstream language style guides.
✓ Method documented✓ Updated May 2026✓ Privacy-first✓ Free · v1.0
Frequently asked
Direct answers; mirrored in this page's FAQ JSON-LD so AI answer engines can cite them cleanly.
What is a case converter?
A case converter rewrites the case of every letter in your text without changing the words themselves. You paste text, pick a target case (UPPERCASE, Title Case, camelCase, etc.), and get the converted version back. It saves you from manually retyping headlines, URL slugs, code identifiers and database column names just to fix their capitalization.
What is the difference between Title Case and Sentence case?
Title Case capitalizes the first letter of every major word (used for book titles, song titles, article headlines): "The Lord of the Rings." Sentence case capitalizes only the first letter of the sentence and proper nouns (used for body copy, modern UI text and most contemporary web headings): "The lord of the rings." Most major sites including Google, GitHub and GOV.UK use Sentence case for headings now; Title Case is still standard for editorial titles.
When should I use camelCase vs snake_case vs kebab-case?
Use camelCase for JavaScript / Java / Swift / Kotlin variables and methods, and for JSON keys in JavaScript-facing APIs (myVariableName). Use snake_case for Python / Ruby / Rust variables and functions, and for SQL column / table names (my_variable_name). Use kebab-case for URL slugs, CSS class names, HTML attributes, and command-line flags (my-variable-name). The choice is a community convention, not a preference: pick the one your language / platform's style guide says.
Does the converter handle punctuation correctly?
Yes. UPPERCASE, lowercase, Title Case, Sentence case and aLtErNaTiNg cAsE preserve all punctuation, spaces and line breaks; they only change the case of letters. camelCase, snake_case and kebab-case treat punctuation and whitespace as word separators, drop them, and join the tokens with the appropriate joiner. Unicode letters (accents, diacritics, non-Latin scripts) are converted with the same standard case-folding the rest of the JavaScript engine uses, so "ümlaut" uppercases to "ÜMLAUT."
Are the rules for Title Case the same everywhere?
Not exactly. The two main English-language style guides (AP and Chicago) overlap on the big rules: capitalize the first / last word and capitalize all major words. They disagree on the exact list of "minor" words. This converter uses the AP / Chicago overlap: short articles (a, an, the), short conjunctions (and, but, or, nor), and short prepositions (of, in, on, to, at) stay lowercase in the middle, but everything else capitalizes. If your style guide differs, edit the output by hand.
Is my text uploaded anywhere?
No. The converter runs entirely in your browser. We don't upload, log, or send a single character to any server. Your text is held in your browser's per-tab session storage so a refresh doesn't lose your work, and it clears the moment you close the tab. The page itself is static HTML; the converter is a small client-side script. Closing the tab is the only privacy guarantee you ever need.
Try the rest of the tools
Same brutalist console, same privacy promise. Pick a counter: