Toggle Case / Inverse Case Converter (flip UPPER ↔ lower)

An inverse case converter (toggle case, flip case, invert case) swaps each letter’s capitalization in place. Hello becomes hELLO. The words stay the same; only the caps flip. That is different from rebuilding alternating case or forcing everything to UPPER CASE or lower case.

What inverse case does

Input	Inverse result
Hello World	hELLO wORLD
iPhone	IpHONE
API_KEY	api_key (letters only; underscore stays)

Non-letters never move. You keep spacing, punctuation, and emoji — useful when you want to reverse a shouty paste or experiment without losing structure.

Inverse vs alternating vs writing case

• Inverse — flip whatever is already there (run twice to undo)
• Alternating — force aLtErNaTiNg from scratch
• Sentence case — readable prose for email and UI
• Title Case — AP / APA / Chicago / MLA headlines

Use inverse when the joke or the fix is “swap the caps I already typed.” Use alternating when you want the classic mock-case rhythm no matter how the paste looked.

When inverse case helps

• Quickly undoing a mixed-caps accident without retyping
• Stylized usernames and chat nicknames
• Puzzle or cipher warm-ups before heavier transforms like Base64 or ROT13

Skip inverse for publication titles and product copy — those need Title Case or Sentence case, not a flip.

How to use this page

1. Paste the text (or drop a .txt file).
2. Confirm Inverse case is selected.
3. Copy the flipped result. Run the mode again to restore, or switch to Alternating case on the same paste.

Microsoft Word’s Change Case menu and Google Docs’ Capitalization tools offer lower / UPPER / title-ish options, but not a true mixed-case toggle. This inverse case converter fills that gap locally.

Related: Alternating case, UPPER CASE, lower case, Capitalized Case, Sentence case.