TDSR(Total debt service ratio)=(payment of principal and interest on mortgage+property tax +heating costs+50% of condominium fees+payments on other personal loan)/grss income. TDSR guidelines Currently range 5 O* N* J$ Y" U+ N- N) A' Cfrom 35% to 42% of gross income. $ m9 [+ u0 w; Z- r/ z% _GDSR(gross debt service ratio)=(payment of principal and interest on mortgage+property taxes+heating costs+50% of condominium fees)/gross income.