# Your Pre-Approval Assumes Income You Can't Actually Document
The letter sits on your kitchen counter. Pre-approved for $650,000. You spend two weekends looking at homes in that range, make an offer on a renovated semi in East York, and then wait for the paperwork to close.
Three weeks later, your broker calls. The underwriter will approve $580,000.
The deal collapses. You are $70,000 short, and nobody warned you this could happen.
Pre-Approvals Use Placeholder Math
A pre-approval is a rate hold with rough affordability guidance attached. The broker takes the income figure you provide, applies a simplified debt service calculation, and issues a letter. That letter does not mean a human underwriter has reviewed your file. It means the lender's system ran a quick screen and found no obvious disqualifiers.
The problem is the income figure. Self-employed borrowers, commission earners, and anyone with variable pay usually quote their best recent year. The broker writes that number into the system. The system spits out a maximum purchase price. The letter goes out.
Then underwriting starts. The broker called Kelly on a Tuesday. She was self-employed, ran a marketing consultancy in Halifax, had been in business six years. Her gross revenue in 2025 was $187,000. She had filed her T1 with that figure, paid the tax, and been pre-approved for $685,000 in July 2026. She made an offer on a house in Clayton Park for $660,000 in August. Firm price, no conditions. The sellers accepted.
Eighteen days later, the underwriter approved her for $565,000.
The sellers kept her deposit. Kelly lost the house and $22,000.
The Pre-Approval Uses Last Year's Number
When you apply for a pre-approval, the broker asks for your income. Self-employed borrowers usually provide their most recent Notice of Assessment. The system accepts that figure, calculates affordability against the stress test rate, contract rate plus 200 basis points, or 5.25%, whichever is higher, and issues a letter.
The underwriter averages your income over two years instead of using a single year.
CMHC requires two years of income history for self-employed borrowers qualifying at prime rates. The underwriter takes your 2024 and 2025 income, averages them, then applies a 15% gross-up to account for business expenses written off on the T1. If your 2024 income was significantly lower than 2025, the two-year average drops your qualifying figure.
Kelly's 2024 income was $138,000. Her two-year average was $162,500. After the 15% gross-up, her qualifying income landed at $186,875. The two-year average was close to her 2025 figure of $187,000, but the underwriter also applied the full stress test calculation, which the pre-approval system had run loosely. Her maximum dropped $120,000 between the letter and the file review.
Commission Income Gets Haircut At Underwriting
If you earn commission, the pre-approval often uses your gross pay from your last few paystubs. The underwriter averages your last two years of commission income and may exclude bonuses that aren't guaranteed. A salesperson who earned $110,000 in base plus $95,000 in commission in 2025, but only $110,000 base plus $52,000 commission in 2024, will see their qualifying income calculated as base plus the two-year commission average: $183,500. The pre-approval might have used $205,000.
Rental income is treated the same way. If you own a rental property and the lease shows $2,400 a month, the underwriter takes 50% of that as qualifying income unless you provide a full year of deposit records and the tenant's signed lease. The pre-approval system often accepts the full lease amount as income.
The Stress Test Runs Twice, Differently
Pre-approval systems apply a version of the stress test, but they use rough debt service ratios and do not always pull your full credit file. The underwriter runs the test again with your actual debts: car loans, lines of credit, minimum credit card payments, property tax, condo fees if applicable, and heating costs.
A buyer pre-approved for $720,000 had $38,000 in car financing and a $15,000 balance on a line of credit at 7.2%. The pre-approval factored in the car loan but missed the line of credit because the broker didn't ask and the system's credit check flagged it as dormant. At underwriting, the lender applied the 3% minimum monthly payment on the line, $450 a month, which reduced the mortgage the buyer could carry by roughly $85,000.
The revised approval came in at $640,000. The buyer had already written a firm offer at $710,000.
What To Ask Before You Write The Offer
Request a full file review before you make an offer, not after. Provide two years of Notices of Assessment if you are self-employed. Provide two years of commission statements if you earn variable pay. List every debt with a balance, every monthly obligation, and your property tax estimate for the home you are buying.
Ask the broker to calculate your maximum using the underwriter's method: two-year income average, full debt load, stress test at the higher of contract plus 200 basis points or 5.25%, and the actual gross-up or haircut your income type requires.
The pre-approval letter will still reflect rough math, because most brokers cannot force a full underwriting review without a live deal. But you will know, within $20,000, what the real number is. That margin matters when the market moves in days and you are deciding whether to write firm or conditional.
Kelly refinanced in 2027, bought a smaller place in Dartmouth, and now asks every self-employed client she advises to run the two-year average before they look at homes. She learned it the way most people learn it, which is the expensive way.
The letter sits on your kitchen counter. Pre-approved for $650,000. You spend two weekends looking at homes in that range, make an offer on a renovated semi in East York, and then wait for the paperwork to close.
Three weeks later, your broker calls. The underwriter will approve $580,000.
The deal collapses. You are $70,000 short, and nobody warned you this could happen.
Pre-Approvals Use Placeholder Math
A pre-approval is a rate hold with rough affordability guidance attached. The broker takes the income figure you provide, applies a simplified debt service calculation, and issues a letter. That letter does not mean a human underwriter has reviewed your file. It means the lender's system ran a quick screen and found no obvious disqualifiers.
The problem is the income figure. Self-employed borrowers, commission earners, and anyone with variable pay usually quote their best recent year. The broker writes that number into the system. The system spits out a maximum purchase price. The letter goes out.
Then underwriting starts. The broker called Kelly on a Tuesday. She was self-employed, ran a marketing consultancy in Halifax, had been in business six years. Her gross revenue in 2025 was $187,000. She had filed her T1 with that figure, paid the tax, and been pre-approved for $685,000 in July 2026. She made an offer on a house in Clayton Park for $660,000 in August. Firm price, no conditions. The sellers accepted.
Eighteen days later, the underwriter approved her for $565,000.
The sellers kept her deposit. Kelly lost the house and $22,000.
The Pre-Approval Uses Last Year's Number
When you apply for a pre-approval, the broker asks for your income. Self-employed borrowers usually provide their most recent Notice of Assessment. The system accepts that figure, calculates affordability against the stress test rate, contract rate plus 200 basis points, or 5.25%, whichever is higher, and issues a letter.
The underwriter averages your income over two years instead of using a single year.
CMHC requires two years of income history for self-employed borrowers qualifying at prime rates. The underwriter takes your 2024 and 2025 income, averages them, then applies a 15% gross-up to account for business expenses written off on the T1. If your 2024 income was significantly lower than 2025, the two-year average drops your qualifying figure.
Kelly's 2024 income was $138,000. Her two-year average was $162,500. After the 15% gross-up, her qualifying income landed at $186,875. The two-year average was close to her 2025 figure of $187,000, but the underwriter also applied the full stress test calculation, which the pre-approval system had run loosely. Her maximum dropped $120,000 between the letter and the file review.
Commission Income Gets Haircut At Underwriting
If you earn commission, the pre-approval often uses your gross pay from your last few paystubs. The underwriter averages your last two years of commission income and may exclude bonuses that aren't guaranteed. A salesperson who earned $110,000 in base plus $95,000 in commission in 2025, but only $110,000 base plus $52,000 commission in 2024, will see their qualifying income calculated as base plus the two-year commission average: $183,500. The pre-approval might have used $205,000.
Rental income is treated the same way. If you own a rental property and the lease shows $2,400 a month, the underwriter takes 50% of that as qualifying income unless you provide a full year of deposit records and the tenant's signed lease. The pre-approval system often accepts the full lease amount as income.
The Stress Test Runs Twice, Differently
Pre-approval systems apply a version of the stress test, but they use rough debt service ratios and do not always pull your full credit file. The underwriter runs the test again with your actual debts: car loans, lines of credit, minimum credit card payments, property tax, condo fees if applicable, and heating costs.
A buyer pre-approved for $720,000 had $38,000 in car financing and a $15,000 balance on a line of credit at 7.2%. The pre-approval factored in the car loan but missed the line of credit because the broker didn't ask and the system's credit check flagged it as dormant. At underwriting, the lender applied the 3% minimum monthly payment on the line, $450 a month, which reduced the mortgage the buyer could carry by roughly $85,000.
The revised approval came in at $640,000. The buyer had already written a firm offer at $710,000.
What To Ask Before You Write The Offer
Request a full file review before you make an offer, not after. Provide two years of Notices of Assessment if you are self-employed. Provide two years of commission statements if you earn variable pay. List every debt with a balance, every monthly obligation, and your property tax estimate for the home you are buying.
Ask the broker to calculate your maximum using the underwriter's method: two-year income average, full debt load, stress test at the higher of contract plus 200 basis points or 5.25%, and the actual gross-up or haircut your income type requires.
The pre-approval letter will still reflect rough math, because most brokers cannot force a full underwriting review without a live deal. But you will know, within $20,000, what the real number is. That margin matters when the market moves in days and you are deciding whether to write firm or conditional.
Kelly refinanced in 2027, bought a smaller place in Dartmouth, and now asks every self-employed client she advises to run the two-year average before they look at homes. She learned it the way most people learn it, which is the expensive way.
Read Next
What 27 Rising Stars Under 40 Reveal About Canada's Next Wealth Model
The Deficit Fell $11.6 Billion. Your Mortgage Rate Didn't Get the Memo.
Banks Call It a Transfer Fee, but It Works Like an Exit Penalty
Leveraged Insurance Ends When Regulators See the Downside, Whatever the Math Says