Free IDN Punycode Converter — Convert International Domain Names to Punycode & Back

What Is an IDN Punycode Converter?

An IDN Punycode converter is an online tool that translates Internationalized Domain Names (IDNs) — domain names containing non-ASCII characters like Chinese, Arabic, Cyrillic, or accented Latin letters — into their Punycode (ASCII-compatible) equivalents, and vice versa.

Punycode is the encoding system defined in RFC 3492 that allows domain names with Unicode characters to work within the existing DNS infrastructure. For example, the domain münchen.de becomes xn--mnchen-3ya.de in Punycode. Our free converter handles both directions instantly.

Why Punycode Matters

The Domain Name System (DNS) was originally designed to handle only ASCII characters. As the internet expanded globally, the need for non-English domain names grew. Punycode bridges this gap:

• Global accessibility — Enables billions of non-English speakers to use domain names in their native scripts
• DNS compatibility — Converts Unicode domains into ASCII strings that DNS servers can process
• Email routing — Email systems require ASCII domain names; Punycode ensures international domains work with email
• Security analysis — Detect homograph attacks where malicious domains use look-alike Unicode characters (e.g., using Cyrillic "а" instead of Latin "a")
• Domain registration — Registrars store domains in Punycode format; understanding the encoding helps with domain management

How Punycode Encoding Works

The Basics

Punycode uses a prefix of xn-- followed by the ASCII-compatible encoding of the Unicode string. The encoding algorithm separates ASCII characters from non-ASCII ones, then encodes the non-ASCII characters using a series of numbers appended to the string.

IDN Structure

An Internationalized Domain Name goes through two layers of processing:

• IDNA (Internationalized Domain Names in Applications) — The protocol that defines how applications handle IDNs
• Punycode — The specific encoding algorithm that converts Unicode labels to ASCII

Examples

• münchen.de → xn--mnchen-3ya.de
• 中文.com → xn--fiq228c.com
• россия.рф → xn--h1alffa9f.xn--p1acf

How to Use the IDN Punycode Converter

1. Open the IDN Punycode Converter tool on this page
2. Enter your domain name — either the Unicode (international) version or the Punycode (xn--) version
3. Click Convert
4. View the converted result — Unicode to Punycode or Punycode to Unicode
5. Copy the result for your domain configuration, DNS setup, or security analysis

Common Use Cases

• Domain registration — Check the Punycode equivalent before registering an international domain
• DNS configuration — Enter the correct Punycode domain in DNS records and server configs
• Phishing detection — Decode suspicious xn-- domains to reveal the actual Unicode characters and spot homograph attacks
• SSL certificate setup — Ensure your SSL certificate covers both the IDN and Punycode versions of your domain
• Email configuration — Set up email servers that handle international domain names correctly

Best Practices

• Always verify conversions — Double-check that the Punycode output matches your intended Unicode domain
• Watch for homograph attacks — Use the converter to decode suspicious domains that may use look-alike characters from different scripts
• Register both versions — If possible, register both the IDN and common misspellings to protect your brand
• Test email delivery — After setting up an IDN for email, test sending and receiving to ensure Punycode routing works correctly
• Use IDNA 2008 standards — Ensure your converter and applications comply with the latest IDNA standards for proper character handling

Related Tools

• DNS Lookup — Check DNS records for any domain, including Punycode domains
• WHOIS Lookup — Look up registration details for international and ASCII domains
• SSL Lookup — Verify SSL certificates for IDN domains
• URL Encoder — Encode special characters in URLs containing international domains
• Safe URL Checker — Check if a Punycode domain is flagged as malicious

Frequently Asked Questions

What does the "xn--" prefix mean?

The xn-- prefix is the ACE (ASCII Compatible Encoding) prefix that identifies a domain label as Punycode-encoded. When a DNS resolver sees "xn--" at the start of a label, it knows to decode it as an internationalized domain name.

Can I use IDN domains for email?

Yes, but support varies. Most modern email servers handle Punycode domains, but some older systems may not. Always test email delivery thoroughly when using an international domain, and ensure your mail server is configured with the Punycode version.

Are IDN domains good for SEO?

IDN domains can perform well in local SEO for non-English markets. Search engines like Google support and index IDN domains. However, for international audiences, an ASCII domain may be easier to share and type. Consider your target audience when choosing between IDN and ASCII domains.

How do I spot a homograph attack?

Homograph attacks use characters from different scripts that look identical — such as Cyrillic "а" vs. Latin "a." If a domain looks familiar but has an xn-- Punycode version you don't recognize, paste it into this converter to reveal the actual Unicode characters and verify the domain's legitimacy.