When I was active runner, I had written a blog about distance running. Then, I was playing with web programming. For that blog I made tempo calculator using HTML and Java Script.
This calculator has data about time, distance and velocity. Distance and velocity data are shown in different units. The tempo calculator calculates one of three data from other two data.
Below is my tempo calculator. Interface is on the Serbian. If someone needs HTML, Java Scrip file, please contact me.