Hi. Go to Forum Q&A and the first post is a sticky that directs you to the Bleach Calculator.

The basic formula for bleach is:
(1,000,000/PV) * BC * Q = FC Added

Where:
PV equal Pool Volume, usually in gallons
BC equals Bleach Concentration as a decimal. So 6% is .06, and 8% is .0825, and 12% is .12
Q equals quantity of Bleach Added, usually in gallons.
FC equals Free Chlorine Added, in ppm (parts per million).

The formula works for gallons or liters as long as you keep the units of PV and Q the same.

I don't know the formulae for the other additives.