What Are GDS/TDS Ratios Anyways?

Matthew Chan • July 5, 2023

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.


CONTACT

Share

RECENT POSTS

How to Legally Assign a Construction Mortgage

By Matthew Chan • August 19, 2026
Why More Mortgage Options Matter—Especially for Assignment Purchases One of the biggest advantages of working with an independent mortgage professional is access to choice. Instead of being limited to one lender and one set of products, mortgage brokers work with multiple lenders—each with different guidelines, risk tolerances, and mortgage solutions. That flexibility becomes especially valuable when your situation doesn’t fit neatly into a “standard” box. A great example of this is purchasing new construction through an assignment contract . Why Assignment Purchases Can Be Challenging Assignment purchases are often viewed as higher risk by traditional lenders. Rather than declining these deals outright, many lenders quietly make them difficult by adding layers of conditions, restrictions, or uncertainty. This can lead to delays, frustration, or financing falling apart late in the process. The Good News There are lenders—available exclusively through the broker channel —that have clear, favourable policies for assignment purchases. With the right lender and proper planning, these transactions are absolutely doable. Typical Financing Requirements for Assignment Purchases While every situation is unique, many lenders that allow assignment financing look for the following: Standard purchase qualification, including income verification, credit, and down payment Assignments accepted at either the original purchase price or current market value Minimum 620 credit score , with no prior bankruptcies or consumer proposals The full down payment must come from the purchaser —seller incentives cannot be used Required Documentation To secure financing, lenders typically require: The original purchase agreement signed by all parties The MLS listing (if applicable) The assignment agreement signed by the builder, original purchaser, and new buyer Any side agreements outlining changes to the purchase price A full appraisal to confirm value This list isn’t exhaustive, but it highlights that while assignment purchases require more coordination, they are very achievable with the right lender and guidance. Final Thoughts Assignment contracts can open doors to great opportunities—but only if your financing supports the transaction. This is where access to multiple lenders and specialized policies makes a real difference. If you’re considering purchasing new construction through an assignment, or if you’d like to explore more traditional purchase options, feel free to connect anytime. I’d be happy to walk you through the mortgage products available and help you choose an option that doesn’t limit your financing possibilities.

Monthly vs. Biweekly Mortgage Payments: Which Is Better?

By Matthew Chan • August 12, 2026
How Mortgage Payment Frequency Affects What You Pay Over Time You’ve probably heard the saying that there are two certainties in life: death and taxes. When it comes to your mortgage, there’s really just one certainty—you’ll repay what you borrow, plus interest. What is flexible, though, is how often you make your mortgage payments. And that choice can have a meaningful impact on how quickly you pay down your mortgage and how much interest you pay over time. The Six Mortgage Payment Frequencies Most lenders offer the following payment options: Monthly – 12 payments per year Semi-monthly – 24 payments per year Bi-weekly – 26 payments per year Weekly – 52 payments per year Accelerated bi-weekly – 26 payments per year Accelerated weekly – 52 payments per year Standard Payment Frequencies The first four options are designed to align with how you get paid. For example: Paid monthly? Monthly mortgage payments may make sense. Paid every two weeks? Bi-weekly payments can align nicely with your cash flow. With these standard options, regardless of how often you pay, the total amount paid over the year is the same —it’s simply divided into more frequent payments. What Makes “Accelerated” Payments Different Accelerated payments work differently—and this is where the real savings happen. With accelerated bi-weekly or accelerated weekly payments, you’re paying a slightly higher amount each time. That extra money goes directly toward reducing your mortgage principal, which lowers the interest you’ll pay over the life of the mortgage. A Simple Example Let’s assume a $1,000 monthly mortgage payment: Monthly: $1,000 once per month = $12,000 per year Semi-monthly: $500 twice per month = $12,000 per year Bi-weekly: $1,000 × 12 ÷ 26 = $461.54 every two weeks = $12,000 per year Accelerated bi-weekly: $1,000 ÷ 2 = $500 every two weeks = $13,000 per year With accelerated bi-weekly payments, you effectively make two extra payments per year without having to think about it. Those extra payments reduce your principal faster, which lowers interest costs over time. Accelerated weekly payments work the same way—you just make smaller payments more frequently. Why This Matters Long Term While it’s difficult to calculate exact savings due to variables like interest rates, terms, and amortization changes, maintaining an accelerated payment schedule over the life of your mortgage can reduce your amortization by up to three years and save a significant amount of interest. The Bottom Line Accelerated payments are a simple, automatic way to lower your overall cost of borrowing—without needing to make lump-sum payments or drastically change your budget. If you’d like to see how different payment frequencies would impact your mortgage specifically, feel free to reach out anytime. I’d be happy to walk through the numbers with you and help you choose the option that fits your goals.

Employment and Mortgage Qualification: What Lenders Look For

By Matthew Chan • August 5, 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.