What Is Punycode? IDN to ASCII (xn--)

If a hostname in WHOIS or a mail log starts with xn--, that is Punycode. DNS still speaks ASCII. Internationalized domain names (IDNs) are stored as ACE labels: ASCII Compatible Encoding, prefix xn--, payload produced by the Punycode algorithm. FlashKit’s Punycode converter runs that algorithm in this tab. It does not register names, does not query WHOIS, and does not prove a name is available.

Worked conversions

münchen.example → xn--mnchen-3ya.example
café.com → xn--caf-dma.com
bücher.example → xn--bcher-kva.example

Conversion is per label. mail.münchen.example encodes only münchen; mail and example stay ASCII. Paste a hostname, not a full URL with a path.

Convert IDN ↔ xn-- in this tab

Unicode in, ACE out (or the reverse). No DNS query for the conversion itself.

Open the Punycode converter

After you have the ACE form

Paste it into the domain-to-IP converter (Google Public DNS, A and AAAA). If there is no record, conversion still succeeded — the name is simply not delegated. Check registrar and expiry with WHOIS. If you are cleaning a messy paste of mixed Unicode hosts, run the domain extractor after you have ASCII labels; the regex is built for host-like tokens, not every Unicode letter.

Homographs

Latin “a” and Cyrillic “а” look the same and encode differently. The converter shows the encoding. It does not flag mixed scripts. If a link’s xn-- form is not the brand you expect, do not log in there.

Frequently asked questions

What is Punycode?

An encoding that represents Unicode DNS labels as ASCII. Internationalized domain names are stored as ACE labels that start with xn--.

Why does my domain start with xn--?

DNS cannot store arbitrary Unicode, so IDNA encodes the label as ASCII starting with xn--. A browser may still display the decoded Unicode form in the address bar.

Does converting Punycode register the domain?

No. Conversion only shows the ACE form. The registrar still has to accept the TLD and the string.