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 2 z0 T4 y- I1 _7 W/ yfrom 35% to 42% of gross income. ! N3 J" S7 m8 r/ J5 E. P+ ^8 SGDSR(gross debt service ratio)=(payment of principal and interest on mortgage+property taxes+heating costs+50% of condominium fees)/gross income.