Mmm... Particulars of unification depends on how you extend SM, but general idea about unification at 10^16 GeV based upon EM/Weak and QCD coupling constants en

Mmm... Particulars of unification depends on how you extend SM, but general idea about unification at 10^16 GeV based upon EM/Weak and QCD coupling constants energy dependence taken directly from SM. Basically, if you plot those coupling constants vs log(E), you'll get their merge at circa 10^16 GeV. That's baseline and it is pretty much pure SM, details are filled differently from different GU theories.