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 ' ~0 o' q: T1 K$ y3 ]4 M$ jfrom 35% to 42% of gross income. % f% k$ v+ D5 I5 vGDSR(gross debt service ratio)=(payment of principal and interest on mortgage+property taxes+heating costs+50% of condominium fees)/gross income.