@tomasbrod is right. It is implemented in the code. Tomas rewrote the staking protocol for V8+, part of which is in the CreateCoinStake function. I rewrote (later) the ETTS stuff, which are the other functions listed.

In any case, if you are referring to doing a web-based calculator, that is a good idea. We would be wise to get gridcoinstats.eu to do it, since that is the main block explorer, and it could use active chain data. We could also end up linking that to the main gridcoin.us site eventually.