Punycode / IDN Converter

Convert a domain to and from Punycode, and see whether it could be imitating another.

What you provide

Domain name

Either the readable form or the xn-- encoded one.

Result

CHECK

xn--mnchen-3ya.de

This domain contains characters outside ASCII, so it is registered as xn--mnchen-3ya.de and only rendered in its readable form by software that chooses to. That gap is what homograph attacks use: Cyrillic а, е and о are visually identical to their Latin counterparts in most fonts, so a domain can be indistinguishable from a brand it is imitating while being an entirely different registration. Browsers defend by showing the Punycode form when a label mixes scripts, which is why a suspicious domain sometimes appears as xn-- in the address bar.

Diagnostic telemetry

ASCII (Punycode)What is actually registered and sent in DNS queries.: xn--mnchen-3ya.de
As entered: münchen.de
Contains non-ASCIINon-ASCII characters can imitate Latin letters closely enough to be indistinguishable in a browser bar.: Yes

What this cannot tell you

Converts and flags non-ASCII characters. It does not judge whether a specific domain is imitating a specific brand — that needs the brand as a comparison, which the lookalike checker does.
Uses the browser's own URL parser rather than a hand-written implementation, because a subtly wrong homograph tool is worse than none.
Runs entirely in your browser. Nothing is looked up, transmitted or stored.

Take this with you

How this calculation works

DNS carries ASCII only, so a domain containing other characters is encoded into an xn-- form before it is queried, and decoded again for display. This converts between them using the browser's own URL parser rather than a reimplementation. The reason it matters beyond convenience is homograph attacks: Cyrillic а, е and о are visually identical to their Latin counterparts in most fonts, so a domain can look exactly like a brand while being an entirely different registration. Browsers defend by displaying the Punycode form when a label mixes scripts, which is why a suspicious domain sometimes shows up as xn-- in the address bar rather than as the name you expected.

What the results mean

ASCII (Punycode): What is actually registered and sent in DNS queries.
As entered: The readable form software chooses to display.
Contains non-ASCII: Whether encoding was needed. If so, visual imitation of another domain is possible.
xn-- prefix: Marks a label as Punycode-encoded. Seeing it in an address bar is usually the browser warning you.

Common problems and fixes

A domain shows as xn-- in my browser: The browser is deliberately refusing to render it, almost always because the label mixes scripts. Treat it as a warning rather than a display glitch.
The two forms look identical: Then the domain is plain ASCII and no encoding was needed. There is nothing to imitate through character substitution.
I want to check a domain against a brand: Use the lookalike checker, which compares against a specific name. This one only tells you whether substitution is possible at all.

Frequently asked questions

What is Punycode?

An encoding that represents non-ASCII domain names in ASCII, so DNS — which carries ASCII only — can handle them. Encoded labels start with xn--.

What is a homograph attack?

Registering a domain that looks identical to another by substituting visually identical characters from a different script. Cyrillic а for Latin a is the classic, and in most fonts the two are indistinguishable.

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

Because the label mixes scripts in a way that could be an imitation. Browsers fall back to the raw Punycode so you can see something is unusual.

Put this on your own site

Free to embed, no attribution required beyond the source link the frame carries itself. It runs entirely in your visitor's browser, sets no cookies and loads no third-party script.

Embed code

<iframe src="https://runthetests.com/embed/punycode-converter/" width="100%" height="560" style="border:1px solid #e5e5e5;border-radius:8px" title="Punycode / IDN Converter" loading="lazy"></iframe>

Preview it at https://runthetests.com/embed/punycode-converter/. Embedded pages are marked noindex, so yours stays the canonical copy — not this one.