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 - }. c5 A9 v _3 p. g9 }from 35% to 42% of gross income. ; \5 K$ H" b% s+ Q, E" \5 b G0 cGDSR(gross debt service ratio)=(payment of principal and interest on mortgage+property taxes+heating costs+50% of condominium fees)/gross income.