What Are GDS/TDS Ratios Anyways?

Tanya Toye • May 7, 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.


Tanya Toye

Mortgage Broker

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Employment and Mortgage Qualification: What Lenders Look For

By Tanya Toye • September 30, 2026
When you apply for a mortgage, your employment history and status carry a lot of weight. Even if you feel secure in your job, lenders need proof that your income is reliable and will continue. To them, your employment status is one of the strongest indicators of whether you can make your mortgage payments long term. Here’s how lenders typically view different employment situations: Permanent Employment This is the gold standard. Once you’ve passed any probationary period and hold permanent status, lenders see you as a lower risk. It shows that your employer is committed to you, and your income is steady. Probationary Periods If you’re still on probation—usually 3 to 6 months, though sometimes longer—lenders may hesitate. That’s because your employer can end your contract without cause during this period. Once probation is over, you’re considered more secure. That said, context matters. If you’ve worked with the same company for years as a contractor and just transitioned into full-time employment, lenders may accept a letter from your employer confirming that probation is waived. Documentation is key here. Parental Leave Being on or about to take parental leave doesn’t mean you can’t qualify for a mortgage. As long as you have a letter from your employer guaranteeing your position and return-to-work date, lenders can use your regular salary—not your leave income—when assessing your application. Term Contracts This is one of the trickiest categories. Even highly skilled professionals with strong incomes can face challenges here. A term contract has a start and end date, which makes lenders question the stability of your future income. To use term-contract income, lenders generally want to see at least two years of history, or proof that your contract has already been renewed. The more evidence you can show of consistent employment, the stronger your case will be. The Bottom Line If you’re planning to apply for a mortgage, it’s important to understand how your employment status could affect your approval. Whether you’re starting a new job, coming back from leave, or working under contract, lenders want documentation that proves your income is reliable. 📞 If you’ve recently changed jobs or are planning a career shift, let’s connect. I can help you prepare your file so you qualify with confidence and avoid surprises in the approval process.

Homeowner Credit is Becoming Part of the Longer-Term Financial Conversation

By Tanya Toye • September 29, 2026
Credit has traditionally been viewed as something you use for a specific purpose: buying a home, financing a major purchase or covering an unexpected expense. But with higher living costs, slower economic conditions and less financial flexibility, credit is increasingly becoming part of a longer-term financial conversation. That doesn’t mean taking on debt indefinitely or relying on borrowing to solve every financial challenge. But it’s important to understand the tools available and the necessity of making thoughtful decisions about when and how credit may fit into your broader financial plan. A Fresh Take on Credit In many ways, households are beginning to approach financial management with more of a business mindset. Businesses regularly evaluate cashflow, consider available sources of financing and balance immediate needs against longer-term objectives. They don’t necessarily borrow simply because credit is available. They consider why they need the funds, what the financing will cost and how it fits into their overall strategy. The same thinking can be useful for homeowners. When household budgets are under pressure, the question isn’t always, “How can I avoid using credit?” It may also be, “What options are available and do any of them make sense for my situation?” That could mean refinancing, consolidating certain debts, using a home equity line of credit or considering another form of financing. The appropriate option depends on your circumstances, objectives and ability to manage the associated costs.  Home Equity May Be Part of the Conversation For homeowners who have built significant equity, your home can represent an important financial resource. That’s one reason I’m seeing more openness to conversations about reverse mortgages. A reverse mortgage isn’t appropriate for everyone, and it shouldn’t be viewed as a simple solution to financial challenges. For the right homeowner and in the right circumstances, however, it may provide access to home equity and improve cashflow without requiring you to sell or move. The important thing is understanding how the option works, what it costs and how it affects your broader financial picture. Credit Requires Discipline Regardless of the type of credit being considered, having a plan is essential. Before taking on additional borrowing costs, it’s worthwhile understanding why you need the funds, how much is appropriate, the overall cost of borrowing and how your longer-term repayment or exit strategy looks. Credit can provide flexibility when financial circumstances are changing. But its value comes from using it intentionally and responsibly – as one part of a larger plan designed to support financial stability and resilience. The goal isn’t simply to borrow more – it’s to understand your options and make credit work within a financial strategy that makes sense for you. Let’s talk about how you may be able to leverage credit to your advantage. Contact Tanya: 604-788-8693 | tanya@tanyatoye.ca