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 J% o* `5 d t" f4 ^. c. D1 i) afrom 35% to 42% of gross income. & M1 g3 Q6 J5 W1 C% R& z) p+ gGDSR(gross debt service ratio)=(payment of principal and interest on mortgage+property taxes+heating costs+50% of condominium fees)/gross income.