Brewing Formulas

I've been collecting useful brewing formulas for awhile now. I update my brew log with them every time I come across something I think I'll need. I tried to identify where I got the information but only found about half. Here is the raw list that I'll try to keep updated when I update my brew log. I hope someone else finds this useful.

Alkalinity = (Calcium / 3.5) + (Magnesium / 7)	Bru'n Water Water Knowledge Sheet
RA = Total Alkalinity - ((Calcium / 3.5) + (Magnesium / 7)	Bru'n Water Water Knowledge Sheet
Gravity Units = (O.G. -1)*1000*Volume	Designing Great Beers, Ray Daniels
(EstSG) GU After Boil = Preboil GU * Preboil Volume / Ending Boil Volume	Designing Great Beers, Ray Daniels
GU Adj w/Extrct = Target GU - Preboil GU / Extrct GU per LB per Gal (Light DME=44)	Designing Great Beers, Ray Daniels
Predicted Final Gravity = ((O.G. - 1)*(1-Attenuation%)) + 1	Designing Great Beers, Ray Daniels
ABV = O.G. – F.G / 7.5 (OG and FG in GUs)
ABV = (og – fg) * 131.25	Brewer's Friend Website
ABV =(76.08 * (og-fg) / (1.775-og)) * (fg / 0.794)	Brewer's Friend Website
ABW = ABV * 7.5
F.G. = 1 - Attenuation as Decimal * GU
Evaporation % =100 - (postboil vol x 100 -;- preboil vol)	BYO Magazine May 2000 Issue, Mr. Wizard
Strike tmp = .2 / ration * msh tmp – gr tmp + msh tmp
Ex Strke tmp = (.2 / 1.25)(152 – 70) + 152 = 165.12 F
AAU = Hop Weight * A.A. %
Scaling Hops = AAU / AA
Scaling Ex. Recipe Calls ½ oz 8.1% you have 5.4%.
.5 * 8.1 = 4.05 AAU
y * 5.4 = 4.05 | y = 4.05 / 5.4 | y=.75 oz of 5.4
Bitterness Ratio = IBUs / O.G.
Degress Plato = S.G. / 4
Recipe Total Gravity = GU * Batch Volume (5.5Gal)
Efficiency = O.G. GU / Recipe Potential GU