InvisiChar

Uppercase & lowercase · local in your browser

Case converter

Convert text to uppercase or lowercase in your browser. No text upload or saving.

Local · no upload

Up to 200,000 UTF-16 units. Text clears when you leave or refresh.

Read only

Spacing and punctuation stay. Some Unicode letters can expand; text without cased letters may stay the same.

Convert uppercase to lowercase, or lowercase to uppercase

Fix text typed with Caps Lock or change its case without retyping. Choose a style and convert, then review the result before copying.

  1. Paste or type into Your text. Try example is available when the input is empty.
  2. Choose Lowercase or Uppercase under Case style, then select Convert text.
  3. Review the read-only result and select Copy result. If copying fails, select the output and copy it yourself.

Editing the input or changing the style clears the old result. Clear removes input, result and status, then returns focus to the input. Leaving this page or refreshing clears your text; copy it yourself before using another tool.

Unicode case conversion can change text length

Hello WORLD! → lowercase: hello world!

Straße → uppercase: STRASSE. The letter ß expands to SS.

İ → lowercase: i̇ (i + U+0307 COMBINING DOT ABOVE). One letter can become two code points.

This tool uses JavaScript’s locale-independent toLowerCase() and toUpperCase(). It does not apply Turkish or other language-specific rules. Unicode versions in browsers can differ. Conversion can be irreversible: changing back does not guarantee the original spelling.

Spaces, punctuation, digits, Chinese text, emoji and combining marks are not trimmed, normalized or deliberately removed. Text with no cased letters can remain unchanged. Browser textareas normalize CR and CRLF line breaks to LF; the result preserves the text received by the textarea, not the original pasted line-break bytes.

The input limit is 200,000 UTF-16 units; output is limited to 600,000 UTF-16 units. JavaScript string length uses UTF-16 units, so some emoji occupy two units per code point. Over-limit input stays intact and no old result is shown. Output beyond its limit is rejected without truncation.

This is not title case, sentence case, grammar checking, safe Unicode cleanup, redaction or original-text recovery.

Copy your text first, then count words and characters or inspect hidden Unicode and review safe cleanup. Nothing is automatically transferred between pages.

Input and output stay only in this page’s memory. Clipboard access is write-only when you click Copy result. Privacy and optional analytics explains fixed event categories and third-party requests.

Last reviewed: 2026-10-24