This is the ratio expressed as a percentage of basic housing costs, plus the monthly payments of any other consumer debts like credit cards, personal loans and vehicle loans, of homeownership to the gross income of the borrower. Basic homeownership costs including mortgage payments (principal + interest), HELOC payments, property taxes, and heat payments (if there are rental properties these costs must also be included in the calculation). Any consumer debt payments like credit cards, personal loans and vehicle loans will be added to the amount and if the property is a condominium, condo (strata/maintenance) fees will also have to be included into the costs. The gross income is typically the before tax income that is reported on line 15000 of your T1-General income tax return and your CRA Notice of Assessment. The formula is TDSR = combined annual home ownership costs + annual consumer debt payments / total income X 100%. (Related item is the GDSR, see definition in this glossary)