IDN Punnycode converter

Translate between international domains and Punycode

Domains can contain letters from almost any language: münchen.de, españa.com, 例え.jp. These are called internationalized domain names (IDNs). But the DNS system underneath only understands basic ASCII letters, digits and hyphens, so every IDN is stored in an encoded form called Punycode, which always starts with xn--. For example, münchen.de becomes xn--mnchen-3ya.de.

This converter works both ways: convert to Punycode/ASCII to get the version you'll need for DNS records, server configs and SSL certificates, or convert to IDN/text to read what an xn-- domain really says.

That second direction matters for security. Attackers register lookalike domains using characters from other alphabets, such as a Cyrillic "а" that looks identical to a Latin "a". Decoding the Punycode reveals the trick.

How to use the idn punnycode converter

1. Paste the domain name or text.
2. Choose Convert to Punycode/ASCII or Convert to IDN/Text.
3. Submit to convert.
4. Copy the result.

Examples

A German city domain

Input: münchen.de

Output: xn--mnchen-3ya.de

Mode: Convert to Punycode/ASCII.

A Japanese domain

Input: 日本語.jp

Output: xn--wgv71a119e.jp

Reading an xn-- domain

Input: xn--espaa-rta.com

Output: españa.com

Mode: Convert to IDN/Text.

Capital letters

Input: MÜNCHEN.DE

Output: xn--mnchen-3ya.de

Domains are case-insensitive, so the result is the same lowercase Punycode.

Common uses

• Adding DNS records or server configuration for an internationalized domain.
• Requesting SSL certificates for IDNs, which use the Punycode form.
• Reading xn-- domains found in logs, emails or links.
• Checking suspicious links for homograph (lookalike) attacks.
• Registering domains in languages with accents or non-Latin scripts.
• Checking a suspicious link: if a domain that looks like a well-known brand turns into an xn-- string, it contains look-alike letters from another alphabet, a common phishing trick.

Tips and things to know

• Each part of the domain (label) is converted separately, so shop.münchen.de becomes shop.xn--mnchen-3ya.de.
• Browsers may show the Punycode version instead of the native characters when a domain mixes alphabets, as a protection against spoofing.
• Check a domain's DNS with the DNS lookup and its registration with the Whois lookup.

Edge cases and limitations

• Enter only the domain. Pasting a full URL like https://münchen.de/page produces a meaningless result, because the slashes and colon aren't valid in a domain label.
• Plain ASCII domains come back unchanged, which is a quick way to confirm a domain has no hidden lookalike characters.
• Emoji convert too (😀.com becomes xn--e28h.com), but most registries, including .com, don't accept new emoji registrations, so such a domain may not exist.
• Each label can be at most 63 characters after encoding.

Frequently asked questions

What is Punycode?

Punycode is a way of writing Unicode characters using only ASCII letters, digits and hyphens, so internationalized domains work in the DNS. Encoded labels start with xn--.

Why does my browser show xn-- in the address bar?

Browsers display Punycode when a domain could be confused with another one, for example when it mixes characters from different alphabets.

Do I need Punycode for my DNS records?

Many DNS dashboards convert automatically, but some require you to enter the xn-- form. Server and certificate configurations usually do.

Are IDN domains bad for SEO?

Search engines support them, but they can be harder for people to type. Many owners also register an ASCII version and redirect it.

Related tools

• DNS Lookup: Find A, AAAA, CNAME, MX, NS, TXT, SOA DNS records of a host.
• Whois Lookup: Get all possible details about a domain name.
• URL encoder: Encode any string input to URL format.
• Slug generator: Generate a URL slug for any string input.