Use the online tool from above to either encode or decode a string of text. For worldwide interoperability, URIs have to be encoded uniformly. To map the wide range of characters used worldwide into the 60 or so allowed characters in a URI, a two-step process is used:
URL encoding stands for encoding certain characters in a URL by replacing them with one or more character triplets that consist of the percent character "%" followed by two hexadecimal digits. The two hexadecimal digits of the triplet(s) represent the numeric value of the replaced character.
The term URL encoding is a bit inexact because the encoding procedure is not limited to URLs (Uniform Resource Locators), but can also be applied to any other URIs (Uniform Resource Identifiers) such as URNs (Uniform Resource Names). Therefore, the term percent-encoding should be preferred.
RFC 3986 does not define according to which character encoding table non-ASCII characters (e.g. the umlauts ä, ö, ü) should be encoded. As URL encoding involves a pair of hexadecimal digits and as a pair of hexadecimal digits is equivalent to 8 bits, it would theoretically be possible to use one of the 8-bit code pages for non-ASCII characters (e.g. ISO-8859-1 for umlauts).
On the other hand, as many languages have their own 8-bit code page, handling all these different 8-bit code pages would be a quite cumbersome thing to do. Some languages do not even fit into an 8-bit code page (e.g. Chinese). Therefore, RFC 3629 proposes to use the UTF-8 character encoding table for non-ASCII characters. The following tool takes this into account and offers to choose between the ASCII character encoding table and the UTF-8 character encoding table. If you opt for the ASCII character encoding table, a warning message will pop up if the URL encoded/decoded text contains non-ASCII characters.