I love Certitude! It has grown to become the go to Coordinate Checker in the Geocaching Community.
You can either have a Keyword Puzzle where you type in the Keyword to obtain the Coordinates, or you type in the solution coordinates to make Homer Dance, Woo Hoo!!!!
However, it is vital that you input the Correct Coordinates or you will recieve a nasty message reminding you to use the Correct Coordinate Format that us used by Geocaching. They even give you an Example of the Correct Coordinates in case you have forgotten the Correct Format.
I saw the Error Message for the first time when I typed this in:
N38 00.HOM W122 00.ERS
Use stealth when looking for cache and watch your step!
You can validate your puzzle solution with certitude.