There are a few games that you can calculate the IGT Times for a total time. Is there a website that I can go to and calculate the IGT Times. Like in some games to where you can calculate all the races final times and put them all together?
There's quite a few sites online for this exact purpose. A quick Google search and I found these:
https://www.ingametime.com/splits
https://solderq35.github.io/fg-time-calc/
Personally, I would just recommend creating a Google Spreadsheet for it. The sheer versatility & customizability of it easily makes it the best option, at least for me. You kinda have to be familiar with how to use it, and if that doesn't really sound like your kind of thing, the above links should be good enough. Hope this helps!
livesplit can do in game time natively as well so you dont need any websites or separate programs