Case Converter
Paste or type text, then convert it to UPPERCASE, lowercase, Title Case, camelCase, snake_case and more — with live character, word, and line counts.
Every case style, one paste
Writers retitle headlines, developers rename variables, and anyone copying text out of an all-caps PDF eventually needs to fix capitalization by hand — one letter at a time if there's no better option. This tool skips that: paste or type text once, then click any of the eleven buttons above to convert the whole thing in place, instantly and entirely in your browser. Use the plain-language cases (UPPERCASE, Title Case, Sentence case, and the two novelty toggles) for prose, or the five programming-style cases (camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE) to turn a phrase into a ready-to-paste variable name, file name, or constant.
Worked examples
Turning a rough headline into publish-ready Title Case
A blogger drafts headlines in lowercase while brainstorming, then needs them capitalized correctly before the post goes live.
- Input
- the ultimate guide to home coffee brewing
- Case
- Title Case
→ The Ultimate Guide To Home Coffee Brewing
Naming one feature three different ways for the codebase
A developer jots down a new feature in plain words, then needs the matching variable name and constant name for the code that implements it.
- Input
- user login attempt
- camelCase
- userLoginAttempt
- CONSTANT_CASE
- USER_LOGIN_ATTEMPT
→ paste once, click twice, done
How each conversion works
The plain-language cases only ever change a letter's upper/lower state. The five programming cases first split the text into words on any run of spaces or punctuation, then rejoin those words using each convention's own rule. Here's every case applied to the same sample text, Hello world, THIS is fun!:
| Case | Rule | Output |
|---|---|---|
| UPPERCASE | Every letter capitalized. | HELLO WORLD, THIS IS FUN! |
| lowercase | Every letter lowercased. | hello world, this is fun! |
| Title Case | First letter of each space-separated word capitalized, rest lowercased. | Hello World, This Is Fun! |
| Sentence case | Lowercased, then the first letter and the first letter after . ! ? capitalized. | Hello world, this is fun! |
| aLtErNaTiNg | Letters alternate lower/upper in sequence, starting lowercase. | hElLo WoRlD, tHiS iS fUn! |
| InVeRsE | Every letter's existing case is flipped. | hELLO WORLD, this IS FUN! |
| camelCase | Words joined with no separator; first word lowercase, rest capitalized. | helloWorldThisIsFun |
| PascalCase | Words joined with no separator; every word capitalized. | HelloWorldThisIsFun |
| snake_case | Words lowercased and joined with underscores. | hello_world_this_is_fun |
| kebab-case | Words lowercased and joined with hyphens. | hello-world-this-is-fun |
| CONSTANT_CASE | Words uppercased and joined with underscores. | HELLO_WORLD_THIS_IS_FUN |
Frequently asked questions
Does converting case change the actual words, or just their capitalization?
For UPPERCASE, lowercase, Title Case, Sentence case, aLtErNaTiNg, and InVeRsE, only letter capitalization changes — spacing, punctuation, and line breaks stay exactly as you typed them. The five programming-style conversions (camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE) go further: they split your text into words on any run of spaces or punctuation and rejoin them using that convention's own rule, so spaces and punctuation marks are removed rather than preserved.
What's the difference between this tool's Title Case and a proper editorial title case?
This converter's Title Case is the simple form: it capitalizes the first letter of every space-separated word, full stop. A style-guide-correct title case additionally knows to keep short words like "a", "of", and "the" lowercase in the middle of a title, per rules that differ between APA, AP, Chicago, and MLA. If you need that level of accuracy, the Title Capitalizer tool (linked below) applies those style-specific rules for you.
Why do camelCase, snake_case, and kebab-case strip out spaces and punctuation?
Those five formats are programming identifier conventions, not prose styles — variable names, file names, and constants generally can't contain spaces or punctuation at all. The converter treats any run of non-letter, non-digit characters as a word boundary, then rejoins the words using capital letters (camelCase / PascalCase), underscores (snake_case / CONSTANT_CASE), or hyphens (kebab-case) so you get a ready-to-paste identifier.
How does Sentence case decide where a new sentence starts?
It lowercases the whole text first, then capitalizes the very first letter and the first letter after any period, question mark, or exclamation point that's followed by a space. That catches ordinary sentence breaks reliably, but it isn't aware of abbreviations like "Dr." or "e.g." — those will also get treated as sentence endings, so it's worth a quick read-through before using the result somewhere formal.
Does any of my text get uploaded or stored anywhere?
No. Every conversion runs as plain JavaScript in your own browser tab — nothing you type or paste is sent to a server, logged, or saved once you close or refresh the page. Clicking Copy or Download only touches your own device (the system clipboard or your downloads folder), not any external service.