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Case Checkerboard (Alternating Case) Tool

Generate or detect checkerboard case: alternating uppercase/lowercase letters (often called “aLtErNaTiNg CaSe”). Choose whether the alternation runs continuously, resets per word, or resets per line.

Category: Text · URL: /tools/case-checkerboard.html
Tip: “Detect” finds the best fit across start-case + pattern modes (continuous / per-word / per-line) using your “ignore non-letters” setting.
Privacy: runs locally in your browser. No uploads, no tracking scripts.

How to use

Use it in two ways: generate checkerboard case, or detect the best-fitting alternating-case pattern.

  1. Paste text into Input.
  2. Select Start with and Pattern (continuous / per word / per line).
  3. Keep Ignore non-letters on if you want spaces and punctuation to not affect the alternation.
  4. Click Convert (to generate) or Detect (to analyze).
  5. Click Copy output to copy the result.
Keywords this page targets (natural cluster): case checkerboard, checkerboard case converter, alternating case generator, alternating uppercase lowercase, spongebob case converter, mocking text alternating case, aLtErNaTiNg cAsE generator, toggle case every letter, checkerboard text case, detect alternating case, alternating case per word, alternating case per line, convert sentence to alternating case, random looking alternating case, text checkerboard capitalization, alternating case tool online, upper lower pattern text, format text in alternating caps, case pattern checker, alternating case copy paste
Secondary intents covered: Convert plain text into alternating upper/lower case for fun or emphasis, Check whether a string already follows an alternating-case pattern, Pick a start letter case (start uppercase vs start lowercase), Control whether the pattern resets at words or lines, Keep punctuation/numbers unchanged while optionally ignoring them for toggling, Copy the transformed output quickly for pasting into chat or docs, Troubleshoot why a string doesn’t match alternating case (mismatch count), Create a consistent alternating-case style for headings or labels

FAQ

What is “checkerboard case”?

It’s alternating letter case (upper/lower/upper/lower…) across text, like HeLlO.

Does the pattern continue across spaces and punctuation?

Yes in Continuous mode; and if “Ignore non-letters” is enabled, only letters flip the pattern.

What does “Reset per word” do?

It restarts the alternation at the first letter of each word, using your selected starting case.

What does “Reset per line” do?

It restarts the alternation after every newline, useful for lists and multi-line text.

How does Detect work?

It compares your text to multiple alternating-case patterns and reports the best match (start case, mode, and match percentage).

Are numbers changed?

No—numbers and symbols are kept as-is. Depending on settings, they may or may not affect toggling.

Is my text sent to a server?

No. This tool runs in your browser and doesn’t make network requests.