Change Case
Convert text to UPPER, lower, Title, Sentence, or swapped case — plus programmer cases like camelCase, snake_case and kebab-case. Runs entirely in your browser, no server, no sign-up.
What this tool does
Convert text from one letter case to another instantly, right in your browser. Nothing is sent to a server — it runs locally, works offline, and needs no sign-up. Paste your text, pick a Case, and copy the result.
Letter cases
These keep your spacing and punctuation and only re-map the letters.
| Case | What it does | Example |
|---|---|---|
| UPPERCASE | Makes every letter a capital. | the quick fox → THE QUICK FOX |
| lowercase | Makes every letter small. | The QUICK Fox → the quick fox |
| Title Case | Capitalizes the first letter of each word. | the quick fox → The Quick Fox |
| Sentence case | Capitalizes the first letter of each sentence. | hello. how are you? → Hello. How are you? |
| Capitalize | Capitalizes only the very first letter. | hELLO wORLD → Hello world |
| swap case | Inverts every letter's case. | Hello World → hELLO wORLD |
| aLtErNaTiNg | Alternates lower/upper across the letters. | hi there → hI tHeRe |
Programmer (identifier) cases
These re-split the text into words — at spaces, symbols, and camelCase
boundaries — and join them in a coding style. So Hello world-foo and
helloWorld both tokenize cleanly.
| Case | Output for Hello world-foo |
|---|---|
| camelCase | helloWorldFoo |
| PascalCase | HelloWorldFoo |
| snake_case | hello_world_foo |
| CONSTANT_CASE | HELLO_WORLD_FOO |
| kebab-case | hello-world-foo |
| Train-Case | Hello-World-Foo |
| dot.case | hello.world.foo |
| path/case | hello/world/foo |
Existing acronyms are handled too: HTTPServer → http_server,
getURLFromAPI → get-url-from-api.
Examples
| Input | Case | Output |
|---|---|---|
the quick brown FOX | Title | The Quick Brown Fox |
straße | UPPER | STRASSE |
hello world. how ARE you? | Sentence | Hello world. How are you? |
Hello World | swap | hELLO wORLD |
helloWorld | snake | hello_world |
My API Key | constant | MY_API_KEY |
FAQ
Is it free and private?
Yes — your input never leaves your device, and it keeps working offline once the page has loaded.
Does it handle accents and non-English letters?
Yes. Case conversion uses
full Unicode mapping, so café → CAFÉ and straße → STRASSE.
What's the difference between Title Case and Sentence case?
Title Case
capitalizes the first letter of every word; Sentence case capitalizes only the
first letter of each sentence (after a ., !, or ?).
Can it convert camelCase to snake_case?
Yes — pick snake_case and it will
split an existing camelCase or PascalCase identifier into words first
(helloWorld → hello_world).
Developer & Automation Access
Run it from the terminal
Same engine as this page, headless — via the gizza CLI:
gizza tool change-case "the quick brown fox"New to the CLI? Get gizza →
Open it by URL
Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:
https://gizza.ai/tools/change-case/?text=the%20quick%20brown%20fox&mode=upperMachine-readable descriptor: tool.json — title + parameters JSON Schema for agents.