Canadian Mortgage Calculators

Start with the affordability calculator if you’re pre-purchase. It qualifies you at the OSFI stress test rate and applies the GDS/TDS limits that lenders use to size your maximum mortgage. This is the same math a broker runs in a pre-qualification conversation. Use the stress test calculator when you already have a rate and want a pass/fail read on GDS and TDS at the Minimum Qualifying Rate.

Once you have a target purchase price, move to the payment calculator to see exactly what your monthly payment will look like at different rates and amortization lengths. Compare a 25-year vs. 30-year amortization side-by-side to see the interest-cost tradeoff.

If you’re a renewal borrower, start with the renewal calculator. It compares your current payment to the renewal payment at today’s rates, models the switch-vs-stay decision, and shows how OSFI’s November 2024 straight-switch rule applies to your specific situation.

For closing-cost planning, the land transfer tax calculator separates out the provincial, municipal, and rebate components by province — critical because Ontario Toronto buyers pay MLTT, BC Vancouver buyers have Speculation and Vacancy Tax, and Alberta buyers pay nothing provincial (just registration fees).

If you are considering leaving a closed mortgage before the term ends, the penalty calculator shows three months’ interest against the interest rate differential, with both posted-rate and contract-rate methods written out. It models a representative lender rather than a named one; actual IRD varies by lender and by which rate the clause uses.

At renewal, the switch cost calculator models the discharge, legal, and optional extras of leaving for a new lender — in dollars and in basis points of your balance. Every total is a Ratellow estimate, not a quote.