Case Converter

What the case converter does

Retyping a headline because it arrived in ALL CAPS is a waste of a perfectly good afternoon. This converter rewrites the capitalization of any text in one step, and it covers both the styles writers use — sentence case, title case — and the styles programmers need, such as camelCase and snake_case.

The result appears as you type, and the Swap button moves it back into the input box so you can chain conversions: force everything to lowercase first, then apply title case for a clean result.

How to use it

Paste your text into the input box.
Pick a style from the left column for ordinary prose, or from the right column for a programming identifier.
Read the result underneath, then use Copy or Download .txt.
Use Swap to move the result into the input and convert again.
Reset in the options panel puts every setting back to its default.

What each style does

lowercase — every letter lowered. Punctuation and numbers are untouched.
UPPERCASE — every letter raised.
Sentence case — the text is lowered, then the first letter of the text and of each new sentence is capitalized. The standalone pronoun I is restored.
Title Case — every word is capitalized except short joining words such as and, of and the, which stay lowercase unless they start or end the title. For style-guide accuracy, use the dedicated Title Case Converter.
Capitalized Case — every word gets a capital, with no exceptions. This is what most people mean by "capitalize each word".
aLtErNaTiNg cAsE — letters alternate lower and upper, skipping over spaces and punctuation so the rhythm stays on the letters.
InVeRsE CaSe — each letter's existing case is flipped.

The identifier styles first break the text into words. Spaces, hyphens, underscores and dots are treated as separators, and existing camelCase boundaries are detected too, so getUserName splits into get / user / name. Acronym runs are handled sensibly: parseHTMLDocument becomes parse / HTML / document, which converts to parse_html_document in snake case.

All case mapping uses the browser's own Unicode tables, so accented Latin, Greek and Cyrillic letters convert correctly. Locale-specific rules that depend on knowing the language — Turkish dotless i is the classic example — cannot be applied automatically.

Examples

Starting from the quick brown fox jumps over the lazy dog:

One phrase in every style
Style	Result
UPPERCASE	THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG
Sentence case	The quick brown fox jumps over the lazy dog
Title Case	The Quick Brown Fox Jumps Over the Lazy Dog
Capitalized Case	The Quick Brown Fox Jumps Over The Lazy Dog
camelCase	theQuickBrownFoxJumpsOverTheLazyDog
snake_case	the_quick_brown_fox_jumps_over_the_lazy_dog
kebab-case	the-quick-brown-fox-jumps-over-the-lazy-dog
CONSTANT_CASE	THE_QUICK_BROWN_FOX_JUMPS_OVER_THE_LAZY_DOG

A practical fix: a spreadsheet column arrives as ANNUAL REPORT SUMMARY. Sentence case turns it into Annual report summary; Capitalized Case turns it into Annual Report Summary. Both take one click, and neither requires retyping 400 rows.

Common use cases

Fixing shouted text. Product feeds and legacy databases love ALL CAPS; sentence case makes them readable.
Preparing headlines for a house style that capitalizes titles.
Renaming variables when moving code between languages — snake_case in Python, camelCase in JavaScript, PascalCase for classes.
Building environment variable names from a description with CONSTANT_CASE.
Making CSS class names or file names with kebab-case.
Cleaning imported data before it goes into a report or a CMS.

Privacy and security

Conversion happens in your browser using the language's own string functions. Nothing is sent to a server, so internal field names, unreleased headlines and customer data can be converted without leaving your machine.

Your chosen style is remembered locally so the tool opens where you left it. Read the privacy policy for the specifics.

Frequently asked questions

What is the difference between Title Case and Capitalized Case?

Capitalized Case capitalizes every word without exception. Title Case leaves short joining words such as a, and, of and the lowercase unless they are the first or last word. Title Case is what publishers use for headlines.

Why did my acronym get lowercased?

In prose styles, an all-caps word is treated as text and converted with everything else. If you need acronyms preserved, convert first and then fix them, or use the Find and Replace tool to restore them in one pass.

Does camelCase handle numbers and symbols?

Numbers are kept and treated as part of the word they touch, so version 2 update becomes version2Update. Symbols other than separators are dropped, because identifiers cannot contain them.

Can I convert several lines at once?

Yes. Prose styles preserve your line breaks, so a whole column of values converts in one step. Identifier styles join everything into a single token, so convert one line at a time if you need separate identifiers.

Is there a limit on text length?

Up to a million characters. Conversion is fast, but very large inputs are worth doing in a couple of batches so the copy step stays responsive.

Tools that pair well with the Case Converter.

Title Case Converter Headline capitalization that follows the style guide you pick. Slug Generator Headline in, clean URL slug out — accents and punctuation handled for you. Whitespace Remover Fix the spacing damage that comes from copying text out of PDFs and web pages. Reverse Text Five reversal modes that keep emoji and combined characters in one piece. Find and Replace Bulk search and replace with optional regular expressions and a live match count. Word Counter Live word, character, sentence and paragraph counts plus reading and speaking estimates.

Converted text