Punycode Converter (IDN Encoder & Decoder)
Convert internationalized domains to and from xn-- ASCII.
About this tool
The DNS only speaks ASCII, so a domain with non-ASCII characters — münchen.de, 日本.jp, пример.рф — is encoded into an ASCII form prefixed with xn-- using the Punycode algorithm (RFC 3492). This converter transforms whole domains in both directions, label by label, so ASCII-only parts pass through untouched.
It's essential for understanding homograph attacks (lookalike domains built from confusable Unicode characters) and for debugging IDN handling. Everything runs in your browser.
Like everything on encrypt.tools, this runs entirely in your browser — nothing you enter is transmitted or stored.
Frequently asked questions about Punycode Converter
What is Punycode used for?+
Punycode encodes Unicode domain names into an ASCII-compatible form (starting with xn--) so the DNS, which only handles ASCII, can route them. Your browser converts a typed Unicode domain to Punycode behind the scenes.
What is an IDN homograph attack?+
Attackers register domains using Unicode characters that look like Latin letters — for example a Cyrillic 'а' in place of Latin 'a' — to impersonate real sites. Converting a suspicious domain to Punycode reveals the xn-- form and exposes the deception.
Why does my domain start with xn--?+
The xn-- prefix marks a label as Punycode-encoded. Everything after it is the ASCII encoding of the original Unicode label. Decode it here to see the real characters.