Swap Case Converter — Invert Every Letter's Case
Toggle the case of every letter — capitals become lowercase and lowercase becomes capitals, instantly. Free, client-side swap case (inverse case) converter.
🔒 100% Client-Side Processing
Your data is processed entirely in your browser and never transmitted to any server.
0 / 100M Limit
Common Use Cases
Repairing Caps Lock text
Invert accidentally-capitalized passages back to intended casing in one click.
Case-sensitivity fixtures
Generate exact case-mirrored variants for testing sort orders and equality logic.
Frequently Asked Questions
- How does swap case differ from the other case tools?
- It toggles each letter individually — uppercase becomes lowercase and vice versa — rather than imposing a uniform style. "PDF file" becomes "pdf FILE", preserving the mixed structure inverted.
- What is a practical use for swapping case?
- Recovering text typed with Caps Lock on ("hELLO wORLD" → "Hello World") and generating inverted-case variants when testing case-sensitive matching, sorting, or password rules.
- Is this the same as Python's str.swapcase()?
- Yes — same behavior: every cased character flips, non-letters pass through unchanged. Python: str.swapcase(). Ruby: String#swapcase. Paste a value here first to confirm what your language's method will produce before writing the code.
- Is my data private when I use this tool?
- Yes. This tool runs entirely in your browser using client-side JavaScript — nothing you type is transmitted to, logged by, or stored on any server. You can safely process confidential text, tokens, or code.