Percent Encoding Explained — What Are %20 and %26 in URLs?

You've seen %20 for spaces and %40 for the @ symbol. These are percent-encoded characters. The system behind this is straightforward once you understand the rules.

How percent encoding works

Percent encoding replaces a character with a percent sign followed by its two-digit hexadecimal ASCII code. Space is ASCII decimal 32, which is hex 20, so space becomes %20. The @ symbol is ASCII 64, hex 40, so it becomes %40.

The characters that are safe in URLs without encoding are:

A-Z  a-z  0-9  -  _  .  ~

Everything else needs to be encoded when used in a URL component.

Common encoded characters you'll encounter

• %20 — space
• %21 — ! (exclamation)
• %22 — " (double quote)
• %23 — # (hash)
• %24 — $ (dollar)
• %25 — % (percent itself)
• %26 — & (ampersand)
• %2B — + (plus)
• %2F — / (slash)
• %3A — : (colon)
• %3D — = (equals)
• %3F — ? (question mark)
• %40 — @ (at sign)

Non-ASCII characters

For characters outside the ASCII range (like Devanagari, Chinese, Arabic, or emoji), the character is first encoded as UTF-8 bytes, then each byte is percent-encoded. This means a single character can produce multiple percent-encoded sequences.

The Hindi word "नमस्ते" in a URL becomes: %E0%A4%A8%E0%A4%AE%E0%A4%B8%E0%A5%8D%E0%A4%A4%E0%A5%87

Reserved characters: context matters

Some characters have meaning in URL structure but can appear unencoded in the right context. A forward slash / is a path separator in the path component but needs to be %2F inside a query parameter value. The rule is: encode the character if it would otherwise be misinterpreted by the URL parser.

Encode and decode any text with our URL Encoder tool.