In short
It sets your real budget before you fall for a house and shows sellers you're serious.
It isn't a guarantee. The lender still has to approve the specific property and your final documents.
What a pre-approval does
A pre-approval is a lender's conditional answer to how much you can borrow, before you've found a home. The lender checks your income, debts, credit and down payment, then runs the numbers at the stress test rate.
Most lenders also hold an interest rate for a set period. Hold periods vary by lender, commonly around 90 to 130 days. If rates drop in the meantime, many lenders give you the lower rate.
A pre-approval also tells you which price range to search in and helps you plan for closing costs, including Ontario land transfer tax. Ottawa has no separate municipal land transfer tax.
What lenders look at
Expect to provide ID, proof of income such as pay stubs, an employment letter or tax returns if you're self-employed, and proof of your down payment. The lender will usually pull your credit report.
Your housing costs and debts are measured against your gross income. For insured mortgages, the limits are 39% for housing costs (GDS) and 44% for all debts (TDS), both calculated at the qualifying rate.
Be complete and honest on the application. Debts or income details that surface later can change or cancel your approval.
If you're buying with a partner, both incomes and both sets of debts are included.
Why it's not a final approval
A pre-approval is conditional. The lender still has to review the specific property, verify your documents and confirm nothing has changed. That review is called underwriting.
Plenty can affect it: a low appraisal, a condo with weak finances, a new car loan, or a job change. Keep your finances steady from pre-approval to closing.
In Ottawa's market, many buyers make offers conditional on financing so their lender can complete this review. If you plan to go firm without that condition, talk to your lender and lawyer first.
If your pre-approval expires before you buy, ask your lender to refresh it. You'll usually provide updated pay stubs and statements, and the rate hold may reset at current rates.
Common questions about pre-approval
How long does a mortgage pre-approval last?
Most rate holds last about 90 to 130 days, depending on the lender. After that you can usually renew the pre-approval with updated documents. The rate hold protects you from rate increases during your search, not from changes in your own finances.
Is a pre-approval a guarantee of a mortgage?
No, a pre-approval is conditional and not a guarantee. The lender still has to approve the property you choose and verify your income, credit and down payment. Final approval comes after underwriting. Treat the pre-approved amount as a ceiling, not a target.
Does getting pre-approved hurt my credit score?
It can have a small, usually temporary effect, because lenders typically pull your full credit report. Rate-shopping within a short window generally has less impact than spreading applications out. Ask the lender what kind of credit check it uses. Checking your own credit report doesn't affect your score.
What documents do I need for a mortgage pre-approval?
You'll usually need government ID, proof of income, proof of your down payment and details of your debts. Salaried buyers often provide pay stubs and an employment letter, while self-employed buyers usually need two years of tax documents. Your lender will confirm its exact list.
General information for Ontario, updated October 2026. Not legal, tax or mortgage advice. Rules change, so confirm with your lawyer, lender or the source above before you rely on it.