URL Encoder Decoder

Why URLs need encoding

A URL can safely contain only a limited set of characters. Spaces, accented letters and symbols such as ampersand, question mark and hash have special meanings or are not allowed, so they are written as a percent sign followed by two hexadecimal digits that give the byte value. A space becomes %20, and the accented letter in São becomes %C3%A3 because it takes two bytes in UTF-8. The URL Encoder Decoder converts in both directions.

Three buttons, three jobs

The tool offers the three conversions web developers use every day.

• Encode uses encodeURIComponent. It escapes almost everything, including slash, question mark, equals and ampersand, so it is right for a single value placed inside a URL, such as one query parameter.
• Encode full URL uses encodeURI. It leaves the characters that give a URL its structure alone (slash, colon, question mark, ampersand, equals, hash), so it is right for a whole address.
• Decode uses decodeURIComponent to turn percent codes back into readable text.

Examples

Encoding the value name=Ada Lovelace&city=São Paulo/Brazil?x=1 as a component gives name%3DAda%20Lovelace%26city%3DS%C3%A3o%20Paulo%2FBrazil%3Fx%3D1. Every structural character is escaped, which is what you want if this text is a single parameter value.

Encoding the whole address https://example.com/a b?q=café&x=1#top with the full-URL button gives https://example.com/a%20b?q=caf%C3%A9&x=1#top. The structure is intact and only the space and the accented letter are escaped.

Plus signs, percent signs and errors

Two details cause most mistakes. First, a literal percent sign must itself be encoded: "100% sure" becomes 100%25%20sure. Second, the plus sign is ambiguous. In an HTML form submission it means a space, but encodeURIComponent writes a real plus as %2B, and decodeURIComponent does not turn plus into a space: a+b decodes to a+b, while a%2Bb also decodes to a+b. If you decode form data, replace plus with a space first.

Decoding a string with a broken percent code, such as one that ends in %E0%A4%A, fails with the message "Invalid URL-encoded string". Check for a truncated copy or for text that was already decoded.

Related tools

To break an address into its protocol, host, path and parameters, use the URL Parser. To make a readable path segment from a title, the Slug Generator is easier than encoding by hand. For binary data in text form, see the Base64 Encoder Decoder. Everything runs in your browser.

Where encoded URLs appear

Percent encoding shows up in query strings from search forms, in links that contain file names with spaces, in redirects that carry another address as a parameter, and in tracking links. When one URL is placed inside another, as in a login redirect, the inner address must be encoded as a component, or its question marks and ampersands will be read as part of the outer URL. Decoding is useful when you want to read a long encoded link in a log file or an analytics report.