Free Punycode converter — IDN ↔ ASCII domain names, both ways

Converts internationalized domain names (IDN) to/from ASCII-compatible Punycode. Runs entirely in your browser.

🌐 Punycode Converter — Free Online Tool

Convert internationalized domains to and from Punycode, free. Punycode (RFC 3492) encodes Unicode domain labels into the limited ASCII letters/digits/hyphen set the DNS allows, producing the xn-- prefixed form used for internationalized domain names (IDNA, RFC 5890). This tool converts a Unicode domain like münchen.de to its xn--mnchen-3ya.de ASCII form and back — in your browser.

🚀 Why use this Punycode Converter tool?

It transliterates internationalized domains to their xn-- ASCII form (and back), so you can see exactly what a browser registers and resolves. 100% free, no registration, and complete privacy — everything runs locally in your browser, so your data never touches a server.

Key Features

🔁Both directions

Encode Unicode → Punycode (xn--…) or decode an xn-- label back to its readable Unicode form.

🌍IDN-aware

Handles accented and non-Latin domain labels per the IDNA standard so the result is what DNS actually uses.

🔒100% private

Conversion runs locally in your browser; nothing you enter is uploaded or stored.

🆓Free, no signup

Unlimited conversions with no account, on desktop and mobile.

Popular Use Cases

Domains & DNS

  • Register an IDN correctly
  • Check the xn-- form
  • Configure DNS/TLS for IDNs

Security review

  • Spot homograph/lookalike domains
  • Audit suspicious xn-- links
  • Verify a phishing report

Development

  • Normalize URLs for comparison
  • Debug IDN handling
  • Email/URL validation

What It Handles

Encode

  • Unicode → xn--
  • Per-label conversion
  • Accents & scripts

Decode

  • xn-- → Unicode
  • Readable domain
  • Round-trip safe

Workflow

  • Both directions
  • Copy result
  • Runs offline

Sources & References

Frequently Asked Questions

What is Punycode and why does it exist?

DNS only allows ASCII letters, digits, and hyphens. Punycode (RFC 3492) encodes Unicode domain labels into that set with an xn-- prefix, so internationalized domain names (IDNs) can work with existing DNS infrastructure.

What does the xn-- prefix mean?

It's the ASCII Compatible Encoding marker that tells software the label is Punycode-encoded Unicode. For example münchen becomes xn--mnchen-3ya.

Why does my browser show xn-- instead of the Unicode name?

Browsers display the xn-- form for labels that mix scripts or look like a known domain, as an anti-spoofing (homograph attack) defense. This tool lets you decode it to see the real characters.

Is my input uploaded anywhere?

No. The conversion happens entirely in your browser; nothing you type leaves your device.

Can Punycode help spot phishing?

Yes. Lookalike domains often hide non-Latin characters; decoding an xn-- label reveals the actual Unicode, helping you spot a homograph attack.

🎓 Pro Tips

  • Tip 1: When auditing a suspicious link, decode its xn-- labels — homograph phishing relies on Unicode characters that look like ASCII.
  • Tip 2: Convert IDNs to Punycode before comparing or storing domains, so two spellings of the same name match.
  • Tip 3: Standards: RFC 3492 (Punycode) and RFC 5890 (IDNA) — https://www.rfc-editor.org/rfc/rfc3492.