camelCase vs snake_case vs kebab-case: When to Use Each

Use camelCase for variables and functions in JavaScript, Java and Swift; PascalCase for class and component names; snake_case for Python variables and database columns; kebab-case for URLs, CSS classes and file names; and CONSTANT_CASE for environment variables and constants. The right choice is mostly set by your language or platform, so the real skill is knowing the convention and converting cleanly when text moves between them.

Here's a reference for every style the Text Case Converter supports, plus the gotchas that trip people up.

Which case should I use?

Style	"Order total amount" becomes	Typical home
camelCase	orderTotalAmount	JS/TS variables and functions, JSON keys, Java and Swift members
PascalCase	OrderTotalAmount	Classes, types, React components, C# methods
snake_case	order_total_amount	Python, Ruby, SQL columns, many REST APIs
kebab-case	order-total-amount	URL slugs, CSS classes, HTML attributes, CLI flags, file names
CONSTANT_CASE	ORDER_TOTAL_AMOUNT	Environment variables, constants
dot.case	order.total.amount	Config keys, i18n message keys, logging namespaces
Title Case	Order Total Amount	Headlines, buttons and menu labels in some style guides
Sentence case	Order total amount	UI copy, email subjects, most body headings
UPPERCASE	ORDER TOTAL AMOUNT	Short labels, acronyms
lowercase	order total amount	Tags, normalized data
aLtErNaTiNg	oRdEr ToTaL aMoUnT	Memes and sarcasm
iNVERSE	oRDER TOTAL AMOUNT	Fixing text typed with Caps Lock on

When a team's style guide disagrees with this table, the style guide wins. Consistency inside one codebase matters more than any universal rule.

How does the converter split words?

The programming styles (camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE and dot.case) first break your text into words, then rejoin them. Words are split at:

• spaces and punctuation, including _, - and .
• a change from lowercase to uppercase (helloWorld → hello + World)
• the end of an acronym (XMLHttpRequest → XML + Http + Request)

So you can convert directly between code styles without going through plain words first:

• first-name → camelCase → firstName
• XMLHttpRequest parser → snake_case → xml_http_request_parser
• getHTTPResponse → kebab-case → get-http-response
• API key rotation policy → CONSTANT_CASE → API_KEY_ROTATION_POLICY

Code styles are applied line by line, so a pasted list of ten field names comes back as ten converted names instead of one long identifier.

Watch out for acronyms

Converting to camelCase or PascalCase rewrites acronyms in their capitalized-word form: user ID number becomes userIdNumber, not userIDNumber. That matches the Google style guides, but some codebases (and .NET for two-letter acronyms) keep acronyms in caps. If yours does, fix those by hand after converting.

The prose styles have their own trap. Title Case and Sentence case lowercase the rest of each word first, so "User ID number" becomes "User Id Number" and "this is NASA" becomes "This is nasa". Re-capitalize proper nouns and acronyms afterwards.

How to convert text case step by step

1. Paste your text into Your text.
2. Under Convert to, click a style. Title Case is selected by default.
3. The Result box updates instantly. Click another style to compare.
4. Use Copy to grab the result, or Download to save it as converted.txt.

Conversion runs in your browser, which is handy when you're renaming fields from a private schema or an internal API.

Common conversions, step by step

API response to Python model. Paste the JSON keys createdAt, lastLoginIp, isActive one per line, choose snake_case and get created_at, last_login_ip, is_active.

Blog headline to URL slug. Paste "10 Tips for Better Sleep" and choose kebab-case to get 10-tips-for-better-sleep. Punctuation such as apostrophes and question marks is dropped as a separator, which is exactly what a slug needs.

Feature flag to environment variable. enableNewCheckout becomes ENABLE_NEW_CHECKOUT with CONSTANT_CASE.

If you only ever need one style, the single-purpose Title Case Converter and Uppercase Converter convert as you type with no buttons to click.

FAQ

What's the difference between camelCase and PascalCase?

Only the first letter. camelCase starts lowercase (orderTotal), PascalCase starts uppercase (OrderTotal). Many languages use camelCase for values and PascalCase for types.

Can I convert a whole file of variable names at once?

Yes. Paste them one per line. Each line is converted on its own and the line breaks are preserved.

Why did my apostrophe disappear in kebab-case?

Apostrophes are treated as word separators in the code styles, so "don't stop" becomes don-t-stop. Remove apostrophes before converting if you'd rather get dont-stop.

Convert your next batch of names with the Text Case Converter.