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Punycode converter

Turn an international domain name like münchen.de or 例子.中国 into the xn-- form that DNS uses, or decode an xn-- name back to readable text. The encoder follows RFC 3492 and is checked against the RFC's own test strings. Nothing is uploaded.

Punycode (ASCII) form

xn--mnchen-3ya.de

    Raw Punycode (RFC 3492)

    Encodes any text, not only domain labels, exactly as in the RFC. Without the xn-- prefix.

    Punycode

    mnchen-3ya

    How it works

    • •Pick a direction and type one domain per line. Each part between dots is handled on its own; parts that are plain letters and digits stay as they are, others become xn-- plus the encoded text.
    • •münchen.de becomes xn--mnchen-3ya.de: the plain letters m, n, c, h, e, n come first, then a code that says where the ü goes.
    • •The Raw Punycode box encodes any text without the xn-- prefix, exactly as the RFC defines it.

    What it does and what it cannot do

    • •Names are lowercased and normalised (NFC) before encoding. The full IDNA mapping table (for example folding full-width letters or ß rules) is not applied, so a few unusual characters may differ from what a registry accepts.
    • •It does not check that a name is registered or allowed by a registry. Some registries only allow certain scripts.
    • •Mixed-script lookalike names (a Cyrillic а in place of a Latin a) are a phishing trick. This tool converts them faithfully, so look at the xn-- form of unfamiliar links.
    • •Each part can be at most 63 characters and the whole name 253, counted in the xn-- form.

    Questions

    What is Punycode?
    A way to write any Unicode text using only the letters, digits and hyphens DNS allows (RFC 3492). Internationalised domain names put xn-- in front so software knows the part is encoded.
    Why does my browser show xn-- in the address bar?
    Browsers show the readable form only when they consider it safe, for example when all letters belong to one script. Otherwise they show xn-- to protect you from lookalike domains.
    How do I use an IDN in DNS or an email server?
    Use the xn-- form wherever software expects ASCII: DNS records, certificates, server configuration. The readable form is for people.
    Does it support emoji domains?
    Yes, the encoder handles any code point, but many registries do not allow emoji in names.
    Is my text uploaded?
    No. Everything is computed in this page.

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