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Punycode Converter (IDN Domains)

Turn münchen.de into xn--mnchen-3ya.de, or decode an xn-- domain to see the real name.

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What is Punycode Converter (IDN Domains)?

The DNS only understands ASCII letters, digits and hyphens. Internationalized Domain Names (IDN) such as bücher.example or 日本語.jp are therefore stored as Punycode (RFC 3492) with an "xn--" prefix on each label that contains non-ASCII characters: bücher becomes xn--bcher-kva. Browsers show the Unicode form but send the Punycode form.

This converter processes each dot-separated label separately, lowercases and normalises (NFC) non-ASCII labels, and leaves ASCII labels alone. It also understands whole lines that hold URLs (only the host changes; path, query and port stay) or e-mail addresses (only the domain part). Direction is detected automatically: if the input contains xn-- it decodes, otherwise it encodes. No lookups are made; the conversion is purely algorithmic.

How does it work?

  1. Paste one or more domain names, URLs or e-mail addresses, one per line if you like.
  2. Leave the direction on Auto-detect, or force Unicode → Punycode or Punycode → Unicode.
  3. Read the result and any warnings (invalid labels, labels above 63 characters), then copy it.

Common use cases

  • Finding the ASCII form of an IDN to use in DNS records, certificates or server configuration.
  • Checking a suspicious xn-- link to see which Unicode characters it really contains.
  • Preparing links for systems that do not accept non-ASCII hostnames.
  • Comparing homograph look-alikes (Cyrillic "а" versus Latin "a") by looking at their Punycode.

Examples

Try this input in the tool above:

Input
münchen.de
bücher.example
日本語.jp
https://☃.net/path?q=1
Output
xn--mnchen-3ya.de
xn--bcher-kva.example
xn--wgv71a119e.jp
https://xn--n3h.net/path?q=1

Privacy

Punycode Converter (IDN Domains) runs entirely in your browser. The text or files you provide are processed on your device and are not uploaded, logged or stored on our servers.

Limitations

This is Punycode only, not the complete IDNA 2008 / UTS #46 processing: it does not check registry rules, allowed scripts or mixed-script safety, and it does not tell you whether a domain exists.

Frequently asked questions

What does xn-- mean?

It marks a DNS label that is Punycode-encoded Unicode. What follows the prefix is the ASCII letters and digits of the name, a hyphen, then a compact code describing the other characters.

Why is only part of my URL changed?

Only the host name uses Punycode. Paths and query strings are percent-encoded instead; use the URL Encoder for those parts.

Can I use it to spot phishing domains?

It helps: an unexpected xn-- prefix means the name has non-ASCII characters, and decoding shows which ones. It does not judge whether a site is safe.

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