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.
Example
Input
Hello World Output
hELLO wORLD Every letter flips, so running it twice returns the original. Characters with no case — digits, spaces, punctuation — pass through untouched.
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.