How to Calculate Your Own Mortgage Pre-Approval Amount in Canada

As mortgage specialists, one of the most common questions we hear from clients is: “How much mortgage can I actually qualify for?”

While nothing replaces a full pre-approval from a lender, many Canadian homebuyers, especially first-timers, want to run the numbers for themselves before taking that step. And that’s smart.

In this post, we will walk you through how to estimate your own mortgage pre-approval amount using the same basic calculations that lenders and brokers use every day.

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Step 1: Understand What Lenders Look At

Mortgage lenders in Canada base your pre-approval on four major factors:

1. Your income
2. Your debts
3. Your credit score
4. Your down payment

Together, these determine what you can afford under the federal mortgage stress test, a required qualification process for most buyers in Canada.

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Step 2: Know the Two Key Ratios

Lenders use two key ratios to calculate your maximum mortgage:

1. Gross Debt Service Ratio (GDS)

This measures how much of your income goes toward housing costs.

• Formula:
  (Mortgage Payment + Property Taxes + Heating + 50% of Condo Fees) ÷ Gross Monthly Income
• Max allowable:
  Up to 39% (depending on credit score and lender)

2. Total Debt Service Ratio (TDS)

This includes all your monthly debt payments.

• Formula:
  (All Housing Costs + Other Debts) ÷ Gross Monthly Income
• Max allowable:
  Up to 44%

If either of these ratios is too high, you may not qualify for the mortgage you’re aiming for.

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Step 3: Estimate Your Gross Monthly Income

Start with your total gross income (before taxes and deductions). Include:

• Salary
• Bonuses or commissions (if consistent and 2 years average are available)
• Rental income (some lenders use 50–95%)
• Child tax benefits or spousal support (in some cases)

Divide by 12 to get your gross monthly income.

Example:
Annual salary: $90,000
Gross monthly income: $90,000 ÷ 12 = $7,500

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Step 4: Add Up Your Monthly Debt Payments

Lenders count the following toward your debt load:

• Car loans or leases
• Credit card minimum payments (typically 3% of balance)
• Student loans
• Personal lines of credit
• Spousal/child support obligations

Example:

• Car loan: $400
• Credit card (balance $5,000): $150
• Student loan: $250
  Total monthly debts: $800

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Step 5: Estimate Your Maximum Housing Budget

Let’s work with the 39% GDS and 44% TDS limits.

Using our example ($7,500 gross income and $800 in other debt):

• Max monthly housing costs (GDS):
  39% × $7,500 = $2,925
• Max total debt (TDS):
  44% × $7,500 = $3,300
• Available for housing after debts:
  $3,300 – $800 = $2,500

So your maximum monthly mortgage-related costs would be the lower of $2,925 and $2,500, which is $2,500.

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Step 6: Estimate the Mortgage You Can Afford

Now let’s translate that $2,500/month budget into a mortgage amount.

Assuming:

• 5-year fixed rate: 4.3%
• 25-year amortization
• No condo fees

You can use a mortgage calculator (or speak with a broker), but a $2,500/month budget at 4.3% over 25 years equals a mortgage of approximately $430,000.

Add your down payment to that for your maximum purchase price.

Example:

• Down payment: $70,000
• Estimated mortgage: $430,000
• Estimated purchase budget: $500,000

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Step 7: Factor in the Stress Test

The mortgage stress test qualifies you at either:

• The contract rate + 2%, or
• 5.25%, whichever is higher

So even if your rate is 4.3%, lenders will qualify you as if you’re paying 6.3%. This lowers your borrowing power slightly, which is why it’s essential to include in your estimate.

If you want a more accurate number, try using a stress test calculator with current rates or ask us to run the numbers for you without a full application.

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Final Thoughts

Estimating your own mortgage pre-approval gives you a head start in the homebuying process. It helps you:

• Set realistic expectations
• Avoid disappointment later
• Shop with more confidence

That said, these are only rough estimates. Your actual pre-approval will depend on your mortgage specialists underwriting, your documentation, and credit score. Working with a mortgage broker can help you compare options, access better rates, and get pre-approved with fewer surprises.

Thinking about getting pre-approved?
We are happy to help you run the numbers, review your credit, and guide you through the process from start to finish. Contact us anytime for a fully underwritten mortgage pre-approval so you can start house shopping with confidence!

At Indi Mortgage, we offer a fresh, modern approach! One that’s simple, transparent, and built entirely around your needs and long term goals. We believe getting a mortgage shouldn’t feel overwhelming. It should feel empowering and exciting!