I used the mr matly calculator. http:
Depends on the OG, but for a 5.25 gallon batch @ OG 1.06, it says if you use 2 vials of yeast you can yield 438 billion cells with a 1.82L starter
A BIG factor is the production date/viability of the yeast vial you receive.
An older vial (90 days) will...