The City of Saskatoon requires a building permit before a secondary suite counts as legal income space, checking egress windows, ceiling height and fire separation along the way. A lender will not add rental income from a suite that cannot produce that paperwork, no matter how finished the space looks.
How much of the income counts also depends on the lender and on the rest of your application against guidelines like a 39 percent gross debt service ratio and a 44 percent total debt service ratio. A mortgage broker who works with secondary suite files can tell you the real number before you offer.
None of this shows up on an online estimate, which prices the house but has no way to confirm a suite is legal or how a lender will treat its income. Get your hand-reviewed valuation from Joel Dyck.