Canadian mortgages compound semi-annually, not monthly, which changes the effective rate calculation compared to what you might expect from other borrowing. If your down payment is under 20 percent, CMHC, Sagen or Canada Guaranty insurance also factors into your qualifying payment, so ask your broker to show the full amortization schedule, not just a monthly figure.
Your down payment source matters too. Minimum down payment is 5 percent up to $500,000 and 10 percent above that, and if you're using the Home Buyers' Plan, up to $60,000 can come from an RRSP, or up to $40,000 from an FHSA at $8,000 a year, both of which a lender will want documented.
A pre-approval is only as good as the documentation behind it, so gather income, down payment source and debt information before you sit down with a broker. Get your hand-reviewed valuation from Joel Dyck.