%3C is the URL-encoded less-than sign (<).
In a URL, %3C stands for the less-than sign (<). Here is when to encode it, what it does in each part of a URL, and what every major language outputs.
Quick facts
| Character | < |
|---|---|
| Name | Less-than sign |
| Unicode | U+003C |
| UTF-8 bytes | 3C (1 byte) |
| Percent-encoded | %3C |
| Lowercase form | %3c — identical meaning |
| Double-encoded | %253C |
| HTML form encoding | %3C |
| RFC 3986 class | Not allowed in URLs |
| HTML entity | < |
What it means in a URL
Not allowed raw in a URL; always encoded as %3C. It is also the character most associated with cross-site scripting, so decoded URL values must be HTML-escaped before they are shown on a page.
RFC 3986 class: Not allowed in URLs. It is outside the characters RFC 3986 permits, so it must always be percent-encoded.
When to encode it
| Where it appears | What to do |
|---|---|
| Path segment | Encode |
| Query value | Encode |
| Fragment | Encode |
| Form body | Encode |
The mistake to watch for
Decoding %3Cscript%3E and inserting it into a page without HTML-escaping it.
What each language produces
Every function in this table encodes it. Output for the single character, UTF-8 input, tested against the real runtimes (see the encoding comparator for your own strings).
| Function | Output | |
|---|---|---|
| JavaScript encodeURIComponent(s) | %3C | encoded |
| JavaScript encodeURI(s) | %3C | encoded |
| JavaScript URLSearchParams | %3C | encoded |
| Python urllib.parse.quote(s) | %3C | encoded |
| Python quote(s, safe="") | %3C | encoded |
| Python urllib.parse.quote_plus(s) | %3C | encoded |
| PHP rawurlencode($s) | %3C | encoded |
| PHP urlencode($s) | %3C | encoded |
| Java URLEncoder.encode(s, UTF_8) | %3C | encoded |
| Go url.QueryEscape(s) | %3C | encoded |
| Go url.PathEscape(s) | %3C | encoded |
| Ruby URI.encode_www_form_component(s) | %3C | encoded |
| Ruby ERB::Util.url_encode(s) | %3C | encoded |
| C# / .NET Uri.EscapeDataString(s) | %3C | encoded |
Decoding it
decodeURIComponent('%3C') returns the less-than sign (<). Python: urllib.parse.unquote('%3C'); PHP: rawurldecode('%3C'). Paste any string into the URL decoder to decode it in your browser.
← %3B Semicolon · Full URL encoding table · %3D Equals sign →
Common questions.
%3C is the percent-encoded form of the less-than sign (<), whose byte value is 0x3C. Decoding the URL turns it back into the character.
Yes. Hex digits in percent-encoding are case-insensitive, so %3c and %3C mean the same thing. RFC 3986 recommends uppercase, and mixing cases can make caches and analytics count one URL as two.
Use your language’s encoder on the value: encodeURIComponent in JavaScript gives %3C, Python’s quote(s, safe="") gives %3C, PHP’s rawurlencode gives %3C.
More from the toolkit.
About this page. Written and maintained by Sri Murugan Systems, the developer of urlencodedecode.com. Character classes follow RFC 3986 §2; language outputs were generated by running each function in its real runtime.