Free IDN to Punycode Converter

How this tool computes its result

Converts domain names between Unicode (international characters) and ASCII Punycode (xn-- prefix) using the punycode library. Converts domain by lowercasing and splitting on ".", then for each label: if it already starts with "xn--," it is passed to punycode.toUnicode(); otherwise it is passed to punycode.toASCII(). The reverse direction applies the opposite logic. Error handling catches any exception and returns a user-facing error message.

Worked example

Input "munchen.de" is split to ["munchen", "de"]. "munchen" does not start with "xn--," so punycode.toASCII("munchen") returns "xn--mnchen-3ya". "de" is already ASCII, so it passes through unchanged. Output is "xn--mnchen-3ya.de". Reversing the process on "xn--mnchen-3ya.de" converts "xn--mnchen-3ya" back to "munchen," producing "munchen.de".

When not to use this tool

This is a character-encoding converter only - it does not verify that a domain exists, that it is registered, or that DNS resolves it; use domain WHOIS or DNS tools to validate domain ownership and accessibility.

Common mistakes

• - Mixing encoded and unencoded labels in one domain - "munchen-xn--mnchen-3ya.de" has a malformed xn-- label that won't convert cleanly; each label should be entirely Unicode or entirely punycode.
• - Pasting a full URL (e.g. "https://munchen.de/path") instead of just the domain - the tool expects domain labels separated by dots, not a full URL with scheme and path, and will treat "/path" as a malformed domain label.
• - Assuming the xn-- prefix is case-insensitive - "XN--" (uppercase) is not recognized by the parser as the punycode marker, and will be treated as a regular label needing ASCII conversion.

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