Web page to tell how far out of the way an added destination is.
This was a small experiment with the Google Maps API, but it turned out to be popular/useful enough to keep around, and do assorted little improvements on.
It works by first calculating how far it is from the original start to the original destination directly, and then via the added destination.
There is a live copy at:
If you copy this, please use your OWN Google API key, rather than running up my request count!