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 $ T% x$ P7 d6 j8 j7 T7 N1 vfrom 35% to 42% of gross income. 9 ~( ~6 |& `3 h% U8 Y% N* K; i3 IGDSR(gross debt service ratio)=(payment of principal and interest on mortgage+property taxes+heating costs+50% of condominium fees)/gross income.