Free Punycode Converter
Convert international domain hostnames between Unicode and ASCII/Punycode in bulk. Inspect both forms, reject invalid names and download local reports.
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How to use the punycode converter
Convert international domain hostnames between Unicode and ASCII/Punycode in bulk. Inspect both forms, reject invalid names and download local reports.
- Paste domains, URLs or common email-address forms, one per line, or import a CSV column.
- Choose Unicode-to-ASCII or ASCII-to-Unicode conversion. The output contains domain hostnames only.
- Set duplicate grouping, order and an optional text filter, then process locally.
- Compare both hostname forms and rejected entries before copying or exporting results.
When you need both forms of a domain
Domain names with accents or non-Latin scripts exist in two forms. People read the Unicode form, such as bücher.de. DNS, mail servers and many configuration files use the ASCII form that starts with xn--. If you work with web servers, email settings, analytics filters or security reviews, you will meet both.
This converter is useful when a hosting panel asks for the ASCII form, when a log file shows xn-- names you want to read, or when you audit a list of links for look-alike domains. Marketers can clean a list of customer email domains. Support teams can check what hostname a pasted link really points to.
A worked example with real domains
Paste these four lines and choose Unicode to ASCII: bücher.de, https://münchen.de/stadt, https://例え.テスト/path and info@bücher.de. The tool reads only the hostname from each line, so the path and the mailbox part are ignored.
The results are xn--bcher-kva.de, xn--mnchen-3ya.de and xn--r8jz45g.xn--zckzah. The email line produces xn--bcher-kva.de again, so with duplicate grouping on it is counted as a duplicate rather than listed twice. Each row also shows the ASCII hostname, the Unicode hostname and the original input side by side.
Switch the direction to ASCII to Unicode and paste xn--bcher-kva.de. The converted column now shows bücher.de. A line such as bad..com is moved to the rejected list with a reason, so you can see what failed instead of losing it.
How the conversion works
Each label of a domain, the parts between dots, is converted on its own. Labels that are already plain ASCII stay as they are. A label with other characters is encoded with the Punycode algorithm and given the xn-- prefix. That is why only the first label of bücher.de changes and the .de ending stays the same.
Before conversion, the hostname is lowercased and checked against DNS rules: each label may hold up to 63 characters and the full name up to 253. IP addresses are rejected because they are not domain names. Full stops written in Chinese or Japanese style are treated as normal dots. Results can be sorted A to Z or kept in input order, filtered by text, and downloaded as TXT, CSV or a JSON report.
Common mistakes to avoid
Do not assume a converted name is safe. Two domains can look the same in Unicode but use different characters, for example a Cyrillic letter in place of a Latin one. Comparing the ASCII forms makes such differences clear, but the tool does not judge who owns a domain.
Also remember that the output holds hostnames only. Paths, query strings and the user part of an email address are not carried over, so keep your original list if you need them. Large lists are fine, but a single batch is limited to 20,000 entries.
Useful tips and limitations
- Unicode domain names can use visually similar characters; conversion does not establish ownership or trust.
- URL and email inputs are used to identify the host; the tool does not rewrite full addresses or send requests.
- When two domains look identical on screen, convert both to ASCII and compare the xn-- strings, since any hidden character difference will show up there.
- Import a CSV and set the column number to convert only the domain column instead of every cell in the file.
Common questions
Does Punycode conversion translate the website name?
No. It changes the representation of an international hostname between Unicode characters and the ASCII encoding used in domain names.
Can the Punycode converter check domain availability?
No. It validates and converts hostname syntax locally without querying DNS or domain registries.
Why does only part of my domain start with xn--?
Punycode works one label at a time. Only labels that contain non-ASCII characters are encoded, so a plain ending such as .com or .de stays unchanged.
Are uppercase letters kept in the result?
No. Hostnames are not case sensitive, so the tool lowercases them before converting. This makes duplicate detection consistent.
Why was an IP address rejected?
An IP address is not a domain name and has no Unicode form. The tool lists it under rejected entries so you can review or remove it.
Text, local files and results are processed in your browser without AI or uploads. Listed domains, links, email addresses and IPs are not contacted. Save a local export before leaving.