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 t0 C6 F2 X {) u8 ~$ j7 a% X6 jfrom 35% to 42% of gross income. ) U2 \) a1 v5 k7 xGDSR(gross debt service ratio)=(payment of principal and interest on mortgage+property taxes+heating costs+50% of condominium fees)/gross income.