URL Encode & Decode

URL encoding (also called percent-encoding) is how the web transports characters that are not safe to appear literally in a URL. A URL can only contain a specific set of characters — letters, digits, and a handful of punctuation marks (hyphen, underscore, period, tilde) — without being ambiguous or breaking the URL parser. Everything else — spaces, slashes that are not path separators, question marks that are not query-string delimiters, ampersands, hash signs, and non-ASCII characters — must be percent-encoded: replaced with a % followed by two hexadecimal digits representing the byte value of the character in UTF-8.\n\nFor example, a space becomes %20, a forward slash becomes %2F, and the Euro sign becomes %E2%82%AC (its 3-byte UTF-8 encoding in hex). This is what happens behind the scenes every time you type a search query into Google — the browser percent-encodes it and appends it to the URL as the q= parameter — and every time an API call includes a value that might contain special characters. If you have ever seen %20 or %3D in your browser's address bar, you have seen URL encoding in action.\n\nThere is an important distinction between encodeURI and encodeURIComponent that trips people up. encodeURI is designed for encoding a full URL, so it leaves many characters intact — colon, slash, question mark, ampersand, hash, equals, and more — because they serve structural roles in the URL itself. encodeURIComponent is designed for encoding a single value that will be placed inside a URL component (a query parameter value, a path segment), and it encodes EVERYTHING that is not 100% safe, including the structural characters. Using the wrong one is a common bug: encodeURI leaves spaces as literal spaces (invalid in a URL), while encodeURIComponent correctly turns them into %20. This tool uses encodeURIComponent by default because the most common use case is encoding a single value — a search term, a username, a filename, or any piece of data that will become one query parameter.\n\nReal-world scenarios where you need URL encoding: manually constructing an API URL with query parameters from user input, creating a redirect URL with dynamic values, building a mailto: link with a subject and body, encoding special characters in a filename for a download link, or percent-encoding OAuth callback parameters. In every case, skipping URL encoding means the URL either breaks, produces a 400 Bad Request, or silently truncates at the first unencoded special character. This tool gives you a quick, reliable way to encode and decode without memorising percent-code tables or guessing which characters need escaping.