URL Encoder Decoder

What this tool does

URL Encoder Decoder converts characters that are not allowed in URLs into percent-encoded UTF-8 bytes such as %20 and %C3%A9, and decodes them back. It offers the same behaviour as encodeURIComponent and encodeURI, a strict RFC 3986 mode, HTML form encoding, and a breakdown of decoded URLs into host, path and query parameters.

URLs may only contain a limited set of ASCII characters. Spaces, accented letters, emoji and reserved symbols such as “&”, “=” and “#” must be percent-encoded, or a link breaks, a query parameter is cut short, or a server reads the wrong value. Each unsafe character is converted to its UTF-8 bytes, and each byte is written as “%” followed by two hexadecimal digits, so “é” becomes %C3%A9.

This tool gives you each encoding flavour explicitly. Component mode matches JavaScript’s encodeURIComponent and is right for a single parameter value. Full-URL mode matches encodeURI and leaves “:/?&=#” intact. Strict RFC 3986 also escapes !'()*, and form mode uses “+” for spaces as HTML forms do (application/x-www-form-urlencoded). When decoding a complete URL you also get a table of its protocol, host, path and every query parameter. Everything runs locally.

How to use URL Encoder Decoder

1. Paste a URL, query string or plain text into the Input box. Several lines can be processed at once.
2. Choose a Mode: an encode option, or Decode.
3. When decoding form data or query strings, keep “Decode + as space” switched on.
4. Turn on “Decode double-encoded input” if you see sequences such as %2520, which is an encoded %20.
5. Read the result, check the URL breakdown table, then copy or download it.

Tips for better results

• Encode each parameter value separately, not the whole URL, so “&” and “=” inside values cannot split your query string.
• Both %20 and + represent a space in query strings, but only %20 is valid in the path part of a URL.
• Hex digit case does not matter: %c3%a9 and %C3%A9 decode identically. RFC 3986 recommends uppercase.
• For OAuth 1.0 signatures and AWS Signature V4, use the strict RFC 3986 mode.

Common use cases

• Building a search link whose query contains spaces and non-English words.
• Reading a long tracking URL with UTM parameters copied from an email.
• Debugging a redirect parameter that has been encoded twice.
• Preparing values for a curl command or an API request.

Common mistakes to avoid

• Using encodeURI on a parameter value: it leaves “&” and “=” untouched, which corrupts the query string.
• Encoding a URL that is already encoded, producing %25 sequences that servers then misread.
• Decoding “+” as a literal plus in a path, or as a space when the API expects a real plus sign.