Encode or decode URLs and query strings — and see every part of a URL broken out.
URLs can only contain a limited set of safe ASCII characters. Anything else — spaces, accents, symbols — is replaced with a percent sign followed by two hex digits, so a space becomes %20 and é becomes %C3%A9.
Component mode (encodeURIComponent) encodes everything except letters, digits and - _ . ! ~ * ' ( ), including characters like / ? & = # that give a URL its structure — use it for a single query value. Full URL mode (encodeURI) leaves those structural characters alone so a whole URL stays valid.
HTML form submissions and many search engines encode spaces in query strings as +. Percent-decoding alone leaves the + as a plus sign, so this tool has a plus-as-space option when decoding query strings.
A % must be followed by exactly two hex digits forming valid UTF-8. A stray % (like in 100%) or a truncated sequence cannot be decoded, and the tool will point that out instead of returning garbage.
No. Encoding and decoding run entirely in your browser.