Finish time calculator

Hi everyone! I'm new here, getting ready for my first half ironman after many years, next October in Sardinia, Italy.
I'm a web programmer and I've developed a tool to estimate the finish time in the main disciplines of triathlon, running, swimming, bike. You can find it here www.racetime-predictor.com
I'd be grateful if you could try it and let me know what you think about it, if you find it useful, how to improve it, etc.

Thanks and have a good day!

Johnnie