Mortgage Approval 101: GDS & TDS Explained

Deb Burnstein • November 5, 2025

Can You Afford That Mortgage? Let’s Talk About Debt Service Ratios

One of the biggest factors lenders look at when deciding whether you qualify for a mortgage is something called your debt service ratios. It’s a financial check-up to make sure you can handle the payments—not just for your new home, but for everything else you owe as well.


If you’d rather skip the math and have someone walk through this with you, that’s what I’m here for. But if you like to understand how things work behind the scenes, keep reading. We’re going to break down what these ratios are, how to calculate them, and why they matter when it comes to getting approved.


What Are Debt Service Ratios?

Debt service ratios measure your ability to manage your financial obligations based on your income. There are two key ratios lenders care about:

  1. Gross Debt Service (GDS)
    This looks at the percentage of your income that would go toward housing expenses only.

   2. Total Debt Service (TDS)
       This includes your housing costs plus all other debt payments—car loans, credit cards, student loans, support payments, etc.


How to Calculate GDS and TDS

Let’s break down the formulas.


GDS Formula:

(P + I + T + H + Condo Fees*) ÷ Gross Monthly Income


Where:

P = Principal

I = Interest

T = Property Taxes

H = Heat


Condo fees are usually calculated at 50% of the total amount


TDS Formula:

(GDS + Monthly Debt Payments) ÷ Gross Monthly Income


These ratios tell lenders if your budget is already stretched too thin—or if you’ve got room to safely take on a mortgage.


How High Is Too High?


Most lenders follow maximum thresholds, especially for insured (high-ratio) mortgages.

As of now, those limits are typically:

GDS: Max 39%

TDS: Max 44%


Go above those numbers and your application could be declined, regardless of how confident you feel about your ability to manage the payments.


Real-World Example

Let’s say you’re earning $90,000 a year, or $7,500 a month.

You find a home you love, and the monthly housing costs (mortgage payment, property tax, heat) total $1,700/month.


GDS = $1,700 ÷ $7,500 = 22.7%


You’re well under the 39% cap—so far, so good.


Now factor in your other monthly obligations:

  • Car loan: $300
  • Child support: $500
  • Credit card/line of credit payments: $700
    Total other debt = $1,500/month


Now add that to the $1,700 in housing costs:
TDS = $3,200 ÷ $7,500 = 42.7%


Uh oh. Even though your GDS looks great, your TDS is just over the 42% limit. That could put your mortgage approval at risk—even if you’re paying similar or higher rent now.


What Can You Do?

In cases like this, small adjustments can make a big difference:

  • Consolidate or restructure your debts to lower monthly payments
  • Reallocate part of your down payment to reduce high-interest debt
  • Add a co-applicant to increase qualifying income
  • Wait and build savings or credit strength before applying


This is where working with an experienced mortgage professional pays off. We can look at your entire financial picture and help you make strategic moves to qualify confidently.


Don’t Leave It to Chance

Everyone’s situation is different, and debt service ratios aren’t something you want to guess at. The earlier you start the conversation, the more time you’ll have to improve your numbers and boost your chances of approval.


If you're wondering how much home you can afford—or want help analyzing your own GDS and TDS—let’s connect. I’d be happy to walk through your numbers and help you build a solid mortgage strategy.


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Deborah Burnstein
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RRSP Home Buyers’ Plan Explained: A Smart Way to Buy Your First Home

By Deb Burnstein • July 8, 2026
Saving for a down payment is one of the biggest challenges first-time buyers face. What many don’t realize is that the Canadian government offers a program designed to make it easier—the Home Buyers’ Plan (HBP) . This program allows you to withdraw money from your RRSP to help purchase your first home, without immediate tax consequences. Here’s how it works: Who Qualifies? To be eligible, you generally need to be a first-time home buyer. In practical terms, this means you must not have owned a home in the past four years, nor lived in a property owned by your spouse or partner during that time. There are also special allowances if you’re living with a disability or helping a relative with a disability. In these cases, you can use the HBP even if you’ve owned a home more recently. How Much Can You Withdraw? Under the program, you can access up to $35,000 from your RRSP as an individual. Couples can combine their withdrawals for a total of $70,000 . These funds must have been in your RRSP for at least 90 days before you take them out. Paying It Back The HBP isn’t “free money”—it’s an interest-free loan from your own retirement savings. You’ll have 15 years to repay the full amount back into your RRSP, starting in the second year after withdrawal. Each year, the CRA will send you an HBP Statement of Account outlining how much needs to be repaid. If you don’t make your repayment in a given year, that amount will be added to your taxable income. Why It’s a Smart Strategy The HBP can give first-time buyers a powerful boost toward homeownership. It helps you put together a larger down payment, which can reduce your mortgage amount and monthly payments. Just remember: it’s important to balance the short-term benefit of homeownership with the long-term impact on your retirement savings. Next Steps Thinking about using the Home Buyers’ Plan? Let’s sit down and review whether it’s the right move for you. Together, we can create a strategy that gets you into your first home while keeping your future financial goals on track. 📞 Reach out anytime—it would be a pleasure to guide you through the process.

Wait! Are You Really Ready to Buy That Home?

By Deb Burnstein • July 1, 2026
So, you’re thinking about buying a home. You’ve got Pinterest boards full of kitchen inspo, you’re casually scrolling listings at midnight, and your friends are talking about interest rates like they’re the weather. But before you dive headfirst into house hunting— wait . Let’s talk about what “ready” really means when it comes to one of the biggest purchases of your life. Because being ready to own a home is about way more than just having a down payment (although that’s part of it). Here are the real signs you're ready—or not quite yet—to take the plunge into homeownership: 1. You're Financially Stable (and Not Just on Payday) Homeownership isn’t a one-time cost. Sure, there’s the down payment, but don’t forget about: Closing costs Property taxes Maintenance & repairs Insurance Monthly mortgage payments If your budget is stretched thin every month or you don’t have an emergency fund, pressing pause might be smart. Owning a home can be more expensive than renting in the short term—and those unexpected costs will show up. 2. You’ve Got a Steady Income and Job Security Lenders like to see consistency. That doesn’t mean you need to be at the same job forever—but a reliable, documented income (ideally for at least 2 years) goes a long way in qualifying for a mortgage. Thinking of switching jobs or going self-employed? That might affect your eligibility, so timing is everything. 3. You Know Your Credit Score—and You’ve Worked On It Your credit score tells lenders how risky (or trustworthy) you are. A higher score opens more doors (literally), while a lower score may mean higher rates—or a declined application. Pro tip: Pull your credit report before applying. Fix errors, pay down balances, and avoid taking on new debt if you’re planning to buy soon. 4. You’re Ready to Stay Put (At Least for a Bit) Buying a home isn’t just a financial decision—it’s a lifestyle one. If you’re still figuring out your long-term plans, buying might not make sense just yet. Generally, staying in your home for at least 3–5 years helps balance the upfront costs and gives your investment time to grow. If you’re more of a “see where life takes me” person right now, that’s totally fine—renting can offer the flexibility you need. 5. You’re Not Just Buying Because Everyone Else Is This one’s big. You’re not behind. You’re not failing. And buying a home just because it seems like the “adult” thing to do is a fast way to end up with buyer’s remorse. Are you buying because it fits your goals? Because you’re ready to settle, invest in your future, and take care of a space that’s all yours? If the answer is yes—you’re in the right headspace. So… Are You Ready? If you’re nodding along to most of these, amazing! You might be more ready than you think. If you’re realizing there are a few things to get in order, that’s okay too. It’s way better to prepare well than to rush into something you're not ready for. Wherever you’re at, I’d love to help you take the next step—whether that’s getting pre-approved, making a plan, or just asking questions without pressure. Let’s make sure your homebuying journey starts strong. Connect anytime—I’m here when you’re ready.