It is an URL Encoding (Percent Encoding) Tool. You can use it to convert normal URL characters into percent encoded characters. Which can be later used for Web Application testing purposes.
Input: <script>alert("Test");</script>
Output: The Encoded String is: %3C%73%63%72%69%70%74%3E%61%6C%65%72%74%28%22%54%65%73%74%22%29%3B%3C%2F%73%63%72%69%70%74%3E