About the Case Converter
This case converter rewrites any block of text into one of eleven casing styles: UPPERCASE, lowercase, Title Case, Sentence case, camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE, aLtErNaTiNg and iNVERSE cASE. It is the quickest fix for a heading typed with caps lock on, a column of database field names that need to become JavaScript properties, or a title that arrived in shouty capitals from a client. The conversion runs locally in your browser and the result can be copied or downloaded as a text file in one click.
How to use the Case Converter
- 1
Paste your text into the 'Your text' box.
- 2
Pick a style from the 'Convert to' menu — the list runs from UPPERCASE through the programming cases to the novelty ones.
- 3
The converted text appears immediately underneath; there is no button to press.
- 4
Use the copy button, or download the result as converted.txt if you are working with a long block.
What people use it for
Rescuing text typed in caps lock
A paragraph that arrived in full capitals is unreadable and cannot simply be lowercased, because the sentence openings would be lost. Sentence case restores the first letter after every full stop, question mark and exclamation mark.
Renaming identifiers between languages
A Python API returning created_at needs to become createdAt in a TypeScript client. Paste the column list, choose camelCase and the underscores are consumed as word boundaries.
Preparing headings for a style guide
Publications that use Title Case need articles and short prepositions kept lowercase. Title Case here leaves 'a', 'the', 'of', 'in', 'to', 'for' and similar words down unless they open the line.
Building CSS class and constant names
kebab-case matches CSS and HTML attribute conventions, while CONSTANT_CASE matches environment variables and exported constants in most languages.
How the programming cases split words
The four identifier styles — camelCase, PascalCase, snake_case, kebab-case — and CONSTANT_CASE all depend on working out where one word ends and the next begins. The converter does this in two passes. First it inserts a boundary wherever a lowercase letter or digit is immediately followed by a capital, which is what turns 'userIDNumber' into recognisable parts and lets you convert an existing camelCase name into snake_case without retyping it. Then it splits on spaces, underscores, hyphens and full stops, discarding empty fragments. The resulting parts are rejoined with the separator the chosen style requires. Two consequences are worth knowing. Acronyms in a row, such as the 'ID' in 'userIDNumber', are treated as a single part because there is no lowercase letter between the capitals, so you get 'user_idnumber' rather than 'user_id_number' — split those manually first. And any punctuation that is not a space, underscore, hyphen or full stop simply disappears, which is usually what you want for an identifier but means the programming cases are unsuitable for converting prose.
Title Case is a house style, not a rule
There is no single correct Title Case. The Chicago Manual of Style capitalises every word except articles, coordinating conjunctions and prepositions of any length. The AP Stylebook capitalises prepositions of four letters or more, so 'Over' is capitalised under AP but not under Chicago. APA capitalises words of four letters or more and every word after a colon. This tool follows a compact, widely accepted list of small words: a, an, the, and, or, but, of, in, on, at, to, for and with. Anything else, including longer prepositions such as 'through' and 'between', is capitalised. The first word of the text is always capitalised regardless. Two edge cases are handled deliberately: words containing an apostrophe are treated as one unit, so 'don't' becomes 'Don't' rather than 'Don'T', and any existing capitals inside a word are normalised, which means an all-caps input converts cleanly instead of staying shouty. Proper nouns, brand names such as iPhone, and Roman numerals will need a manual touch-up afterwards.
Tips
- Convert to lowercase first if your source is all capitals and you want Title Case — it avoids odd mixed results.
- Split acronyms with a space or underscore before converting to snake_case so 'user ID' becomes user_id, not userid.
- Sentence case only capitalises after terminal punctuation, so proper nouns will need restoring by hand.