Case Converter Online
Change text to uppercase, lowercase, sentence case and more. Preview the converted result beside your original, then copy or download it without overwriting your source.
Conversion updates automatically. This English version uses English casing rules. Sentence case is a basic punctuation-based conversion; review names, acronyms, abbreviations and the pronoun “I”.
How to change text case
1. Enter your original
Type or paste the text you want to reformat into the first box.
2. Choose a case
Select a conversion style. Compare the result with the unchanged source.
3. Copy or download
Copy the converted text or save it as a UTF-8 TXT file.
Which text case should you choose?
A case converter changes letter capitalization. It is useful for fixing a draft typed with Caps Lock, standardizing a list or trying a different presentation without retyping the text.
| Style | Result |
|---|---|
| Sentence case | Hello world |
| lowercase | hello world |
| UPPERCASE | HELLO WORLD |
| Capitalized Case | Hello World |
| Alternating case | hElLo WoRlD |
| Inverse case | HELLO WORLD |
Uppercase and lowercase
Uppercase converts letters with case to capitals. Lowercase converts them to their lowercase forms. Numbers, ordinary punctuation and letters without uppercase or lowercase forms are left unchanged. These conversions do not correct spelling or grammar.
Sentence case versus capitalized case
Sentence case first lowercases the text, then capitalizes the first letter at the beginning of the text and after common sentence-ending punctuation or a line break. It uses simple rules rather than linguistic sentence detection.
Capitalized case uppercases the first letter of each matched word and lowercases the rest. Apostrophes within words are kept together, so “DON’T STOP” becomes “Don’t Stop”. Hyphenated parts are treated separately. This is not an editorial title-case system: it does not apply APA, Chicago or other style-guide rules for small words.
Alternating and inverse case
Alternating case starts with a lowercase letter and alternates between lowercase and uppercase. Spaces, numbers, punctuation and characters without case do not advance the pattern. The pattern continues across words and lines.
Inverse case switches uppercase letters to lowercase and lowercase letters to uppercase. For example, “Hello” becomes “hELLO”. Unicode mappings can expand letters, so the result may contain more characters than the source and may not be reversible.
Accents, Unicode and text length
The tool uses English locale-aware Unicode casing. Accented letters such as é can become É. Some mappings expand a single letter: German ß becomes SS when uppercased. Arabic letters do not have uppercase and lowercase forms and remain unchanged.
Each character total counts Unicode code points, not visual grapheme clusters or UTF-8 bytes. For more detailed length analysis, use the Character Counter. For reading-time estimates and word frequency, use the Word Counter.
Privacy and text handling
This tool’s code converts your text in your browser. It does not send the text to an API or save it in browser storage. Copy result writes to your clipboard only when clicked. Download TXT creates a local UTF-8 file without a byte-order mark.
Your browser, extensions and other scripts installed on the website have their own behavior, which this tool does not control.
Frequently asked questions
Will the converter overwrite my original text?
No. The original stays in the first box. Every conversion is calculated from that original and displayed separately.
Does sentence case recognize names and acronyms?
No. It lowercases the text before applying basic capitalization. Review names, acronyms such as NASA, abbreviations, decimal points and the standalone pronoun “I” yourself.
Does capitalized case follow title-case style guides?
No. It capitalizes every matched word, including words such as “and” and “the”. Apply your publication’s title rules separately.
Are spaces and line breaks preserved?
Yes. The tool does not trim your text, collapse spaces or remove line breaks. The TXT download preserves the line breaks present in the source textarea.
Why can the converted text have a different length?
Unicode casing can map one character to several characters, such as ß to SS. The source and result counters show their lengths independently.
Does it work with every language?
It accepts Unicode text, but this page uses English casing rules. Languages with different casing conventions may need a different locale. Scripts without letter case, including Arabic, are not given artificial uppercase or lowercase forms.