WN8
http://blog.noobmeter.com/2013/10/wn8-rating-alpha-testing.html
[SPOIL]The exact formulas are:
rDAMAGE = avgDmg / expDmg
rSPOT = avgSpot / expSpot
rFRAG = avgFrag / expFrag
rDEF = avgDef / expDef
rWIN = avgWinRate / expWinRate
rWINc = max(0, (rWIN - 0.71) / (1- 0.71))
rDAMAGEc= max(0, (rDAMAGE-0.22) / (1-0.22))
rFRAGc = min(rDAMAGEc+0.2 , max(0, (rFRAG-0.12) / (1-0.12)))
rSPOTc = min (rDAMAGEc+0.1 , max(0, (rSPOT-0.38) / (1-0.38)))
rDEFc = min (rDAMAGEc+0.1 , max(0, (rDEF-0.10) / (1-0.10)))
WN8 = 980*rDAMAGEc + 210*rDAMAGEc*rFRAGc + 155*rFRAGc*rSPOTc + 75*rDEFc*rFRAGc + 145*min(1.8,rWINc)
The coefficients for tanks used to calculate all the exp* ratings in case of WN8 are published here:
http://www.noobmeter.com/tankList[/SPOIL]
(WN7 thì khỏi cần quan tâm nữa)