Uppercase and lowercase converter
Convert text to UPPERCASE, lowercase, Sentence case or Title Case in one click. Also camelCase, snake_case and other code cases, URL slugs, reversed text and whitespace cleanup.
The text has no letters with upper and lower case. Characters such as Japanese, Korean and digits are left unchanged.
How to use
- Paste or type your text into the input box.
- Choose a conversion (UPPERCASE, Title Case, camelCase, URL slug and more). The result updates instantly.
- Optionally pick whitespace cleanup steps: trim each line, collapse repeated spaces, remove empty lines or join everything into one line. Cleanup runs before the conversion; choose "No case change" to only clean up.
- Press "Copy result" to copy it, or "Download .txt" to save it as a text file.
Notes and limits
- Up to 200,000 characters.
- Scripts without letter case, such as Japanese and Korean, and digits are left unchanged. Full-width Latin letters stay full-width.
- No conversion deletes letters of any script. Code cases such as camelCase remove punctuation and spaces, which act as word separators.
- Sentence case also lowercases proper nouns and the word "I", and treats abbreviations such as "e.g." as the end of a sentence. Fix these by hand if needed.
- Title Case follows the simple rule described below. It does not follow a particular style guide such as AP or Chicago.
- URL slugs keep letters of every script (for example Korean or Cyrillic). If you need an ASCII-only slug, transliterate the text first.
How it works
Case mapping uses the standard Unicode tables in a way that does not depend on your device language. Language-sensitive conversion would give different results on different devices; for example, a Turkish setting turns "i" into a dotted "İ". The German "ß" becomes "SS" in uppercase.
Sentence case: the text is lowercased, then the first letter of the text and the first letter after ".", "!" or "?" followed by a space or line break are capitalized.
Title Case: the first letter of each word (separated by spaces, hyphens or slashes) is capitalized and the rest lowercased. With the option on, short English words such as a, an, the, and, or, of, to, in and on stay lowercase unless they start or end a line.
camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE and dot.case: each line is split into words at characters that are not letters, digits or combining marks, and at lowercase-to-uppercase changes, then joined again.
aLtErNaTiNg case: only letters with case are counted, alternating lower and upper, starting lowercase on each line.
Reverse: the text is split into user-perceived characters (grapheme clusters) with Intl.Segmenter, so emoji, flags and accented letters stay intact.
URL slug: lowercased, accents removed from Latin letters (é becomes e), and everything that is not a letter or digit replaced with "-".
FAQ
What is the difference between Title Case and Sentence case?
Title Case capitalizes the main words, as in "The Lord of the Rings", and is used for headings and titles. Sentence case capitalizes only the first word of each sentence, as in normal writing.
Does it work with Japanese or Korean text?
These scripts have no upper and lower case, so they are left as they are. Only letters that have case, such as Latin, Greek and Cyrillic, are converted. Whitespace cleanup and reverse work for every script.
Why does the slug keep non-Latin letters?
Deleting them would lose the meaning. Modern browsers display such URLs and percent-encode them automatically when sending a request.
Is my text sent anywhere?
No. The conversion runs in your browser, and the text is not sent or stored.
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