Normalization Collision

How to use

1. List identifiers

   Paste filenames, user IDs, or database keys with one value per line.

2. Choose a form

   Start with NFC. Use NFKC or NFKD only when compatibility characters are relevant.

3. Review the originals

   Compare source lines and code points, then decide which spelling is authoritative.

Scope of the result

The checker does not reproduce operating-system, database, or locale-specific collation. It reports only collisions produced by Unicode normalization.

Frequently asked questions

Should I use NFC or NFD?

Follow the contract of the destination system. This tool does not choose a standard; it shows which originals collide under the selected form.

Can I replace everything with NFKC?

That is not recommended. Compatibility normalization can change the meaning of units, symbols, and presentation characters.

Are my identifiers uploaded?

No. Normalization and grouping happen only in your browser.