I am having a hard time finding the requirements on a per viewer basis on LIVE streaming. I know that I need to build an HLS server. I am good with that. I just do not know how much bandwidth per viewer I am going to need. Say I have 10,000 people that are going to watch my live feed of an event. HOW MUCH bandwidth am I going to need? What formula is there? Is there even a formula? I need to know and hope someone is willing to answer it for me!
It'll vary on your stream quality, but figure around 2-5mbps. So, you can do the math of a viewer into a minute/hour of megabyte per second x 60 x 60.
Dacast has an informative website that explains alot of this, even an estimator. You should look into them, they offer a per-event billing which is rare in streaming anymore. Starts around $200 and likely would cover your first stream or two if not more.