I think the sticking point of a lotion calculator would be the e-wax. I see sellers call it e-wax, conditioning e-wax, Polawax (which is a specific brand) but there is no recipe or list of ingredients or any type of numerical values on the package that I see. I suppose you could figure out an average of how much oil + water 1 ounce (or 1 gram or whatever) would be emulsified by (some unit of measure) of e-wax. But then other ingredients do factor in, I think. It's my understanding (and I could be totally wrong here) that solid waxes (beeswax, soy wax), stearic acid and cetyl alcohol contribute to / support emulsification. So I think that if you have a recipe that has stearic and e-wax, and you totally remove the stearic, you would need more e-wax.