Case converter
Convert text to any case instantly. 12 conversion types including camelCase, snake_case and more.
Ctrl + L clear | Ctrl + Shift + C copy output
Why we say "uppercase" and "lowercase"
The names come from the printing workshop. Hand typesetters in the 1500s kept their metal letters in two wooden cases: capital letters in the case mounted higher on the desk — the upper case — and the small letters, needed far more often, within easy reach in the lower case. The terminology outlived the technology by centuries. Before printing, scribes called the two letterforms majuscule and minuscule, and some writing systems never developed the distinction at all: Arabic, Hebrew, Chinese and Georgian have no concept of letter case, which is why case conversion is a peculiarly Latin-alphabet problem.
Case conversion types explained
UPPER CASE converts every letter to uppercase. lower case converts every letter to lowercase. Title Case capitalizes the first letter of every major word while keeping small words like "a", "the", and "and" lowercase. Sentence case capitalizes only the first letter of each sentence.
Capitalized Case capitalizes the first letter of every single word including small words. Alternating case switches between upper and lower for every character. Inverse case flips the case of every letter — uppercase becomes lowercase and vice versa.
camelCase removes spaces and capitalizes the first letter of each word except the first — used in JavaScript and Java for variable names. PascalCase is like camelCase but capitalizes the first word too — used in class names. snake_case replaces spaces with underscores and lowercases everything — common in Python and databases. kebab-case replaces spaces with hyphens — used in URLs and CSS. CONSTANT_CASE is snake_case in all caps — used for constants in programming.
When to use each case type
- UPPER CASE — headings, emphasis, acronyms, shouting in text
- lower case — casual writing, usernames, email addresses
- Title Case — article titles, book titles, headings in formal documents
- Sentence case — body text, social media posts, most general writing
- camelCase — JavaScript variables, Java methods, JSON keys
- PascalCase — class names in most programming languages
- snake_case — Python variables, database columns, file names
- kebab-case — URL slugs, CSS class names, HTML attributes
- CONSTANT_CASE — environment variables, constants in code
Frequently asked questions
Should headlines use title case or sentence case?
It depends on the style guide you follow. American publishing tradition — AP, Chicago, The New York Times — uses Title Case, capitalizing every major word. British publications and most modern tech companies, including Google and Apple in their interface text, have moved to sentence case, which reads as friendlier and avoids endless judgment calls about which words count as "major". Whichever you choose, consistency matters more than the choice — pick one, and use the converter's Title Case and Sentence case buttons to enforce it across all your headings.
How do I fix text accidentally typed in ALL CAPS?
Paste it and click Sentence case — the tool lowercases everything, then re-capitalizes the first letter of each sentence, turning an accidental caps-lock paragraph back into normal prose in one click. This beats retyping, and it is the classic rescue for form data, subject lines and old documents typed in caps. One caveat applies to any automatic converter: proper nouns like names and places come out lowercase, so give the result a quick scan and fix the handful of words that need their capitals back.
Why do programmers use camelCase?
Because code identifiers cannot contain spaces, programmers need a way to keep multi-word names readable, and camelCase — myVariableName — solves it by capitalizing each interior word. It became the house style of Java and JavaScript, while Python standardized on snake_case and most languages use PascalCase for class names. The convention is old: chemists were writing compound names this way long before computers, and camelCase notation was well established by the 1970s at Xerox PARC. The converter's camelCase, PascalCase, snake_case and kebab-case buttons translate between all these conventions instantly.
What is the difference between snake_case and kebab-case?
Only the separator: snake_case joins words with underscores (user_first_name) and kebab-case with hyphens (user-first-name). Where each belongs is settled convention — snake_case rules Python code and database columns, while kebab-case rules URLs and CSS class names. The URL preference has an SEO reason: search engines treat hyphens as word separators, so /text-tools is read as two words, historically more reliably than /text_tools. Pick the one your destination expects and convert with one click.
Can I convert multiple paragraphs or a whole list at once?
Yes. The converter processes your entire input regardless of length — paste a full document and every paragraph transforms together. For lists, enable Bulk mode and each line is treated as an independent string, so converting twenty product titles to Title Case handles each title separately rather than treating the list as one long sentence. You can also chain conversions: click "Use as input" to feed a result back in and apply a second transformation.