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 ' D3 t* H* Y6 ?8 ?3 Q1 t Q& Ofrom 35% to 42% of gross income. 1 Z4 A2 e, X5 v) P( x4 U' kGDSR(gross debt service ratio)=(payment of principal and interest on mortgage+property taxes+heating costs+50% of condominium fees)/gross income.