Home Affordability Calculator

GDS (Gross Debt Service) measures your housing costs — mortgage principal and interest, property tax, heating, and half of any condo fees — as a share of gross income, capped at 39%. TDS (Total Debt Service) adds all your other debt payments on top of housing costs, capped at 44%. Lenders qualify you against whichever ratio produces the lower maximum.

The OSFI-mandated stress test requires you to qualify at the higher of 5.25% or your actual contract rate plus 2%, even though you'll pay the lower contract rate. It exists to confirm you could still afford the payment if rates rose, and it's applied to both insured and uninsured mortgages.

Mortgage default insurance is required whenever your down payment is less than 20% of the purchase price. The premium is a percentage of the mortgage amount that scales down as your down payment percentage rises, and it's typically added to the mortgage principal rather than paid upfront.

A larger down payment reduces the mortgage amount needed for the same purchase price, which lowers your monthly payment and housing-cost ratios — and once you reach 20% down, it also removes the CMHC insurance premium entirely, freeing up more borrowing room.

Yes — both are included in the GDS calculation alongside your mortgage payment, since lenders treat them as unavoidable costs of owning the home. Condo fees are counted at 50% of the monthly amount if applicable. Underestimating these costs is a common reason people overestimate how much they can afford.