URL Encoding Special Characters Table: %20, %3B, %2F, Unicode

URL Encoding Special Characters: Fast Answers

Need the encoded value for a URL character right now? Use this special characters table to find common percent encodings like space = %20, semicolon = %3B, slash = %2F, plus = %2B, and Unicode/UTF-8 characters such as é = %C3%A9. These are the encodings developers most often need when fixing broken links, API query strings, file names, redirects, and form submissions.

Why You Need a URL Encoding Reference

URL encoding, also called percent-encoding, turns unsafe URL characters into a % followed by two hexadecimal digits. The rules are simple once you know the context: encode reserved characters when they are data, leave URL delimiters alone when they are structure, and encode Unicode as UTF-8 bytes. This reference is organized so you can quickly answer questions like "what is %20?", "should / be %2F?", "what does %3B mean?", and "how do I encode Unicode in a URL?"

Complete Special Character URL Encoding Table

Here are the standard ASCII special characters and their percent-encoded forms. Use the "Encode when..." column to decide whether the character is URL syntax or data that must be escaped:

Safe (Unreserved) Characters That Never Need Encoding

RFC 3986 defines a set of unreserved characters that can always appear in URLs without encoding. These are completely safe in any URL context: A–Z (uppercase letters), a–z (lowercase letters), 0–9 (digits), and the four special characters hyphen (-), underscore (_), period (.), and tilde (~). If your data consists only of these characters, no encoding is needed. Encoding these characters (which is technically allowed but unnecessary) just adds overhead without adding safety. Note that the tilde (~) was previously considered "unsafe" in an older RFC but is now explicitly unreserved in RFC 3986. This matters because some older systems may still percent-encode the tilde as %7E — this is equivalent but unnecessarily verbose.

Common Extended Latin and European Characters

International characters require multi-byte UTF-8 encoding. Here are frequently encountered characters from European languages:

Emoji and 4-Byte Characters

Emoji and characters from supplementary Unicode planes use 4 UTF-8 bytes and produce longer percent-encoded sequences. Here are some common examples:

The Space Problem: %20 vs. +

The space character has two different encodings depending on the context, and this causes more confusion than almost any other URL encoding topic. In percent-encoding per RFC 3986, a space is encoded as %20. This is the correct encoding for path segments and is also valid in query strings. In application/x-www-form-urlencoded format (HTML form submissions), spaces are encoded as +. Many URL parsers accept both, but the difference matters in specific scenarios. If you send a URL with a + in the path, many servers will treat it as a literal plus sign, not a space. Similarly, a + in a query value that was encoded with encodeURIComponent() represents a literal plus sign, but if the same URL was form-encoded, the + means a space. The safest approach: use %20 for spaces in paths, redirects, and copyable URLs, and be consistent with + vs. %20 in query strings throughout your application.

Control Characters and Non-Printable Characters

Control characters (ASCII 0–31 and 127) and non-printable characters must always be percent-encoded in URLs. Here are the most commonly encountered ones: Newline (\n, ASCII 10) encodes as %0A. Carriage return (\r, ASCII 13) encodes as %0D. Tab (\t, ASCII 9) encodes as %09. Null character (\0, ASCII 0) encodes as %00. Delete (ASCII 127) encodes as %7F. These characters should not appear in URLs at all, but if user input or data contains them, they must be encoded. The null byte (%00) is particularly important from a security perspective — some systems use null bytes to terminate strings, and an unencoded null byte in a URL can lead to security vulnerabilities. Always sanitize and encode user-supplied data before including it in URLs.

Quick Reference: Most Common URL Encodings

For quick day-to-day reference, here are the 15 most commonly needed percent-encoded values that developers encounter: %20 = space, %21 = !, %22 = ", %23 = #, %24 = $, %25 = %, %26 = &, %27 = ', %28 = (, %29 = ), %2B = +, %2C = ,, %2F = /, %3A = :, %3D = =, %3F = ?, %40 = @. Save this list or bookmark this page for quick access when debugging URL encoding issues. Our free URL encoder/decoder tool can also instantly encode or decode any character or string — just paste it in and click encode.

Frequently Asked Questions

What is %20 in URL encoding?

%20 is the percent-encoded form of a space character. Use %20 for spaces in URL paths, file names, redirect URLs, and any context where you want the space to be unambiguous.

Should a space be encoded as %20 or +?

Use %20 for standard URL percent-encoding. Use + only when you are working with application/x-www-form-urlencoded data, such as HTML form submissions or query strings generated by form encoders.

What does %3B mean in a URL?

%3B is the encoded form of a semicolon (;). Encode semicolons when they are part of a value so they are not interpreted as a path parameter separator or sub-delimiter.

What does %2F mean in URL encoding?

%2F is the encoded form of a forward slash (/). Encode / when the slash is data inside a path segment, file name, token, or query value rather than a path separator.

How do you URL encode Unicode characters?

Convert the Unicode character to UTF-8 bytes, then percent-encode each byte. For example, é becomes the bytes C3 A9, so its URL-encoded form is %C3%A9.

Which URL characters do not need encoding?

The unreserved characters A-Z, a-z, 0-9, -, _, ., and ~ do not need URL encoding. Reserved characters like &, =, ?, /, ;, and # should be encoded when they are data.