On this page,
http://www.brewersfriend.com/brix-converter/
The formula used for brix to sg is listed as
Brix -> SG Equation:
SG = (Brix / (258.6-((Brix / 258.2)*227.1))) + 1
(Source: Brew Your Own Magazine)
But if you follow the link, that equation is for Plato (not brix). While plato, balling...