大小写转换器
按Unicode默认映射把文本转换为小写、大写、标题式、句首式或反转大小写，保留空格、制表符、换行、标点、符号和emoji位置，并支持复制与TXT下载。
使用步骤
如何使用
- Paste up to 100,000 characters.
- Choose lowercase, uppercase, title, sentence, or toggle case.
- Review the result, then copy it or download a TXT file.
Five explicit conversion modes
Lowercase and uppercase use the browser’s default Unicode mappings. Toggle case switches each caseable character independently. Title Case treats runs of Unicode letters, numbers, and combining marks as words, so punctuation and whitespace remain separators. Sentence Case lowercases the text, then uppercases the first cased character at the start and after sentence punctuation.
Structure and Unicode boundaries
Spaces, tabs, line breaks, punctuation, numbers, symbols, and emoji stay in their original positions. Unicode case mappings can expand a character, such as ß becoming SS in uppercase, so output length can exceed input length. The tool accepts up to 100,000 UTF-16 characters and does not preserve all-caps abbreviations or apply language-specific editorial rules.
常见问题
你可能还想知道
Does title case preserve acronyms?
No. Title Case applies the documented word rule and does not infer or preserve abbreviations such as API or NASA.
What counts as a word?
A word is a run of Unicode letters, numbers, or combining marks. Punctuation, symbols, and whitespace stay between words and are not moved.
Can Unicode case conversion change length?
Yes. Default Unicode mappings can expand or contract text, so the output is limited by the 100,000-character input boundary rather than a fixed character-for-character size.