What is Percent-Encoding (URL Encoding)?

A URL was originally designed to carry only a limited set of ASCII characters. Put a space, a non-Latin letter, or a special character like ? or & directly into an address and different browsers or servers may interpret it differently, or it may break. The fix is percent-encoding — what people usually call URL encoding.

What %XX means

Percent-encoding replaces an unsafe character with its byte value in hexadecimal, prefixed by %. A space becomes %20, a question mark becomes %3F. A character made of several bytes, like most non-Latin letters, gets one %XX per UTF-8 byte.

• space → %20
• ? → %3F
• & → %26
• € (UTF-8) → %E2%82%AC

Why UTF-8

The modern web treats UTF-8 as the standard. The browser's encodeURIComponent converts text to UTF-8 bytes and then turns each byte into %XX. That means the same character always encodes the same way, and decoding restores the original text exactly.

This site's encode/decode tool uses the browser's built-in functions, so your input is converted instantly and never sent to a server.

When you need it

You need percent-encoding whenever you drop an arbitrary string into part of an address — a link containing a search term, a query parameter value, or a redirect target URL placed inside another URL. Without encoding, an & or = in the value can be mistaken for a separator and cut the parameter short.