Punycode IDN Converter
Translate Unicode domain labels to ASCII-compatible Punycode and back.
Represent international labels in DNS-compatible ASCII
Internationalized domain names let labels contain Unicode while the DNS wire ecosystem continues to use ASCII. Punycode encodes each non-ASCII label with the RFC 3492 bootstring algorithm and adds the xn-- marker. This tool processes labels independently, preserves dots, and reverses marked labels back to Unicode without contacting DNS or checking whether a domain exists.
The default bücher.example becomes xn--bcher-kva.example. Decoding that ASCII form returns the original umlaut label. Basic ASCII characters stay readable before the delimiter, while non-ASCII code points are represented through adaptive base-36 deltas. Case and normalization choices matter, so visually similar input strings can encode to different labels.
Do not mistake readable Unicode for a trust decision
Punycode conversion does not validate registration policy, Unicode normalization, script mixing, confusable characters, certificates, or ownership. A readable Unicode result can still be deceptive in a phishing context. The algorithm runs in your browser and sends no lookup. Use a trusted IDNA library and security policy when validating production hostnames, because IDNA adds mapping rules beyond raw Punycode.
Frequently Asked Questions
Why do encoded domain labels start with xn--?
That prefix marks an ASCII-compatible encoded label so IDN-aware software knows to apply Punycode decoding.
Does this check whether the domain exists?
No. It performs local text conversion only and makes no DNS or registration request.
Is raw Punycode conversion full IDNA validation?
No. IDNA also defines mapping, normalization, contextual, and script-related rules for hostnames.
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