Punycode Encoder

Summary

Convert Unicode domain names to Punycode (xn--...) and back, instantly in your browser.

How it works

1. Paste or type a Unicode domain name (e.g. münchen.de) into the input box.
2. Click "Encode to Punycode" to convert each label that contains non-ASCII characters to its xn-- ACE form.
3. Click "Decode to Unicode" to convert xn-- ACE labels back to the original Unicode characters.
4. Individual labels are processed independently — ASCII-only labels pass through unchanged.
5. Copy the result with the Copy button or clear the form to start over.

Use cases

• Verify the Punycode representation of an internationalized domain before DNS registration.
• Debug IDN issues in email headers, TLS certificates, and web applications.
• Convert localized domain names for use in HTTP Host headers or SMTP EHLO commands.
• Cross-check ACE labels returned by WHOIS or DNS resolvers against their Unicode originals.
• Prepare Punycode values for inclusion in configuration files or code strings.
• Validate that a decoded Punycode label round-trips back to the expected Unicode form.

Frequently Asked Questions