What is Text Case Converter?
Letter Case Converter prepares titles, constants, test data, batch copy, and code comments as uppercase, lowercase, title case, sentence case, or toggled case. It preserves line breaks, spacing, numbers, and punctuation while relying on browser Unicode and locale-aware case mapping for scripts that have uppercase and lowercase forms. Common workflows include the following. Turn ordinary text into the casing needed for a title or constant. Inspect mixed-case test data and interface copy. Normalize English text copied from logs, spreadsheets, or older systems. The page also documents input boundaries, output behavior, and practical cautions so you can review the result before putting it into an application, configuration, test, or production workflow.
When to use it
- Turn ordinary text into the casing needed for a title or constant.
- Inspect mixed-case test data and interface copy.
- Normalize English text copied from logs, spreadsheets, or older systems.
How to use it
- Paste the text to transform.
- Choose a case mode.
- Convert and review proper names and acronyms.
- Load one of the realistic examples first to verify the selected options and processing direction before replacing it with your own data.
- Review the output, status message, and documented limits; copy, download, or continue only after the result matches your expectation.
Runnable examples
The “Example 1” and “Example 2” buttons load the matching inputs. They cover different structures, directions, or boundaries and can be run directly in the workspace.
Example 1
hello JSONLane. SECOND line!
中文 Text 2026Example 2
release NOTES: tools 21-30 are READY.
keep URLs and API names under review.Input rules
- Input may contain multiline Unicode text, digits, whitespace, and punctuation.
- Scripts without letter case, including Chinese, remain unchanged.
- Title and sentence modes use character boundaries rather than a brand or publishing style guide.
- Text input is counted before processing and is limited to 200,000 characters on this page; file modes apply the separate file limit shown in the workspace.
- Proper names and brand casing require review.
Output rules
- Line breaks and original whitespace positions are preserved.
- Toggle mode changes only characters that have case variants.
- Locale-specific results depend on the browser's Unicode and language implementation.
- Output reflects only the current input, direction, and options; rerun after changing a mode or value instead of treating an earlier result as current.
- Locale rules depend on the browser.
Limitations and cautions
- Proper names and brand casing require review.
- Locale rules depend on the browser.
- Title mode is not a grammar or editorial checker.
How your data is handled
Character traversal and case mapping happen only in the browser tab, with no uploads, translation service, or saved conversion history.