GDS/TDS Ratios Explained

Deb Burnstein • May 21, 2025

One of the major qualifiers lenders look at when considering your application for mortgage financing is your debt service ratios.


Now, before we get started, if you prefer to have someone walk through these calculations with you, assess your financial situation, and let you know exactly where you stand, let’s connect. There is no use in dusting off the calculator and running the numbers yourself when we can do it for you!


However, if you’re someone who likes to know the nitty-gritty of how things work instead of simply accepting that's just the way it is, this article is for you. But be warned, there are a lot of mortgage words and some math ahead; with that out of the way, let’s get started!

 

“Debt servicing” is the measure of your ability to meet all of your financial obligations. There are two ratios that lenders examine to determine whether you can debt service a mortgage.


The first is called the “gross debt service” ratio, or GDS, which is the percentage of your monthly household income that covers your housing costs. The second is called the “total debt service” ratio, or TDS, which is the percentage of your monthly household income covering your housing costs and all your other debts.


GDS is your income compared to the cost of financing the mortgage, including your proposed mortgage payments (principal and interest), property taxes, and heat (PITH), plus a percentage of your condo fees (if applicable).


Here’s how to calculate your GDS.


Principal + Interest + Taxes + Heat / Gross Annual Income


Your TDS is your income compared to your GDS plus the payments made to service any existing debts. Debts include car loans, line of credit, credit card payments, support payments, student loans, and anywhere else you’re contractually obligated to make payments.


Here’s how to calculate your TDS.


Principal + Interest + Taxes + Heat + Other Debts / Gross Annual Income


With the calculations for those ratios in place, the next step is to understand that each lender has guidelines that outline a maximum GDS/TDS. Exceeding these guidelines will result in your mortgage application being declined, so the lower your GDS/TDS, the better.


If you don’t have any outstanding debts, your GDS and TDS will be the same number. This is a good thing!


The maximum ratios vary for conventional mortgage financing based on the lender and mortgage product being offered. However, if your mortgage is high ratio and mortgage default insurance is required, the maximum GDS is 39% with a maximum TDS of 44%.


So how does this play out in real life? Well, let’s say you’re currently looking to purchase a property with a payment of $1700/mth (PITH), and your total annual household income is $90,000 ($7500/mth). The calculations would be $1700 divided by $7500, which equals 0.227, giving you a gross debt service ratio of 22.7%.


A point of clarity here. When calculating the principal and interest portion of the payment, the Government of Canada has instituted a stress test. It requires you to qualify using the government's qualifying rate (which is higher), not the actual contract rate. This is true for both fixed and variable rate mortgages.


Now let’s continue with the scenario. Let’s say that in addition to the payments required to service the property, you have a car payment of $300/mth, child support payments of $500/mth, and between your credit cards and line of credit, you’re responsible for another $700/mth. In total, you pay $1500/mth. So when you add in the $1700/mth PITH, you arrive at a total of $3200/mth for all of your financial obligations. $3200 divided by $7500 equals 0.427, giving you a total debt service ratio of 42.7%.


Here’s where it gets interesting. Based on your GDS alone, you can easily afford the property. But when you factor in all your other expenses, the TDS exceeds the allowable limit of 42% (for an insured mortgage anyway). So why does this matter? Well, as it stands, you wouldn’t qualify for the mortgage, even though you are likely paying more than $1700/mth in rent.


So then, to qualify, it might be as simple as shuffling some of your debt to lower payments. Or maybe you have 10% of the purchase price saved for a downpayment, changing the mortgage structure to 5% down and using the additional 5% to pay out a portion of your debt might be the difference you need to bring it all together.


Here’s the thing, as your actual financial situation is most likely different than the one above, working with an independent mortgage professional is the best way to give yourself options. Don’t do this alone. Your best plan is to seek and rely on the advice provided by an experienced independent mortgage professional. While you might secure a handful of mortgages over your lifetime, we do this every day with people just like you.


It’s never too early to start the conversation about mortgage qualification. Going over your application and assessing your debt service ratios in detail beforehand gives you the time needed to make the financial moves necessary to put yourself in the best financial position.


So if you find yourself questioning what you can afford or if you want to discuss your GDS/TDS ratios to understand the mortgage process a little better, please get in touch. It would be a pleasure to work with you, we can get a preapproval started right away.

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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.