IDN Punnycode converter

Translate IDN to ASCII and decode them back. This free IDN Punnycode converter needs no signup. Paste your Unicode URL to see the raw DNS format.

How the idn punycode converter works

Browsers and DNS only understand ASCII. When you register a domain with Cyrillic, Kanji, or Arabic characters, the registry encodes it using Punycode. This algorithm maps Unicode to the limited ASCII character set defined in RFC 3492. The output always starts with the ACE prefix xn--. You type a human-readable address. The resolver queries the encoded string.

The conversion process is entirely reversible. Encoding compresses the non-ASCII characters into a base-36 representation while leaving standard ASCII letters untouched. Decoding reverses the math to reconstruct the original Unicode glyphs. You just need to know which direction you are translating. It is not a lossy compression. Every original character survives the round trip perfectly.

• The xn-- prefix tells DNS resolvers this label is encoded.
• Encoding applies to each domain label separately, split by dots.
• Pure ASCII labels pass through without any modification.

When to use an online IDN Punnycode converter

You will hit this wall when configuring DNS records manually. Cloudflare and AWS Route53 sometimes reject raw Unicode in CNAME or TXT records. You need the Punycode version to make the API accept your payload. It also happens when reading server logs. Apache and Nginx write the requested URI in its encoded form. Debugging becomes much easier once you decode it.

Security teams use this to spot homograph attacks. A malicious actor registers a domain that looks like your brand but uses Cyrillic characters instead of Latin ones. The visual difference is zero. The Punycode output reveals the trick immediately. You see the encoded string and realize the underlying characters do not match your actual trademark.

• Pasting internationalized URLs into legacy terminal tools.
• Debugging HTTP 400 errors caused by malformed encoded headers.
• Verifying SSL certificate subject alternative names.

Limits of this free IDN Punnycode converter

This tool translates strings. It does not perform DNS lookups or check if the domain actually resolves. If you paste an invalid Unicode string, the encoder will still output a mathematically valid Punycode string. The registry will just reject it later. You are responsible for validating the input format before you push it to production.

Some older systems struggle with the output. Windows command prompt historically choked on certain Unicode characters before decoding. If your target application expects a specific normalization form like NFC or NFD, this tool outputs the standard canonical representation. It will not fix broken UTF-8 byte sequences or handle mixed-script labels that violate registry rules.

How to use the idn punycode converter

1. Paste your Unicode domain or Punycode string into the input field.
2. Select the conversion direction from the dropdown menu.
3. Click the convert button to process the string.
4. Copy the resulting ASCII or Unicode text from the output box.
5. Clear the input field to start a new translation.

Common domain encoding examples

See how different scripts translate into the ASCII-compatible encoding.

Frequently asked questions

Is this tool really free to use?

Yes. You can run as many conversions as you need without creating an account or paying a fee. The interface is completely open to the public and does not restrict your daily usage.

Why does my decoded domain still look like gibberish?

You might be looking at a URL-encoded string instead of Punycode. URL encoding uses hex sequences for spaces, while Punycode uses the specific prefix. Make sure you are decoding the correct format for your specific use case.

Does this work on mobile browsers?

Yes. The interface is responsive and adapts to smaller screens. You can paste and copy text just like you would on a desktop without any layout breaking.

What happens if I paste a domain that is already pure ASCII?

The tool leaves it exactly as it is. Pure ASCII labels do not require encoding, so the output matches your input character for character without adding any unnecessary prefixes.

Can I convert an entire URL with a path and query string?

No. This tool only processes the domain name labels. You must strip the protocol, path, and query parameters before pasting the text to ensure accurate translation.