What Are GDS/TDS Ratios Anyways?

Diane Buchanan • August 30, 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.


DIANE BUCHANAN
 Mortgage Broker

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Home Reno Dreams? Let’s Talk Mortgage Financing

By Diane Buchanan • June 3, 2026
How to Use Your Mortgage to Finance Home Renovations Home renovations can be exciting—but they can also be expensive. Whether you're upgrading your kitchen, finishing the basement, or tackling a much-needed repair, the cost of materials and labour adds up quickly. If you don’t have all the cash on hand, don’t worry. There are smart ways to use mortgage financing to fund your renovation plans without derailing your financial stability. Here are three mortgage-related strategies that can help: 1. Refinancing Your Mortgage If you're already a homeowner, one of the most straightforward ways to access funds for renovations is through a mortgage refinance. This involves breaking your current mortgage and replacing it with a new one that includes the amount you need for your renovations. Key benefits: You can access up to 80% of your home’s appraised value , assuming you qualify. It may be possible to lower your interest rate or reduce your monthly payments. Timing tip: If your mortgage is up for renewal soon, refinancing at that time can help you avoid prepayment penalties. Even mid-term refinancing could make financial sense, depending on your existing rate and your renovation goals. 2. Home Equity Line of Credit (HELOC) If you have significant equity in your home, a Home Equity Line of Credit (HELOC) can offer flexible funding for renovations. A HELOC is a revolving credit line secured against your home, typically at a lower interest rate than unsecured borrowing. Why consider a HELOC? You only pay interest on the amount you use. You can access funds as needed, which is ideal for staged or ongoing renovations. You maintain the terms of your existing mortgage if you don’t want to refinance. Unlike a traditional loan, a HELOC allows you to borrow, repay, and borrow again—similar to how a credit card works, but with much lower rates. 3. Purchase Plus Improvements Mortgage If you're in the market for a new home and find a property that needs some work, a "Purchase Plus Improvements" mortgage could be a great option. This allows you to include renovation costs in your initial mortgage. How it works: The renovation funds are advanced based on a quote and are held in trust until the work is complete. The renovations must add value to the property and meet lender requirements. This type of mortgage lets you start with a home that might be more affordable upfront and customize it to your taste—all while building equity from day one. Final Thoughts Your home is likely your biggest investment, and upgrading it wisely can enhance both your comfort and its value. Mortgage financing can be a powerful tool to fund renovations without tapping into high-interest debt. The right solution depends on your unique financial situation, goals, and timing. Let’s chat about your options, run the numbers, and create a plan that works for you. 📞 Ready to renovate? Connect anytime to get started!

Buying a Vacation Property or Rental? Here’s What Lenders Look For

By Diane Buchanan • May 27, 2026
Owning a vacation home or an investment rental property is a dream for many Canadians. Whether it’s a cottage on the lake for family getaways or a rental unit to generate extra income, real estate can be both a lifestyle choice and a smart financial move. But before you dive in, it’s important to know what lenders look for when financing these types of properties. 1. Down Payment Requirements The biggest difference between buying a primary residence and a vacation or rental property is the down payment. Vacation property (owner-occupied, seasonal, or secondary home): Typically requires at least 5–10% down, depending on the lender and whether the property is winterized and accessible year-round. Rental property: Usually requires a minimum of 20% down. This is because rental income can fluctuate, and lenders want extra security before approving financing. 2. Property Type & Location Not all properties qualify for traditional mortgage financing. Lenders consider: Accessibility : Is the property accessible year-round (roads maintained, utilities available)? Condition : Seasonal or non-winterized cottages may not meet standard lending criteria. Zoning & Use : If it’s a rental, lenders want to ensure it complies with municipal bylaws and zoning regulations. Properties that fall outside these norms may require financing through alternative lenders, often with higher rates but more flexibility. 3. Rental Income Considerations If you’re buying a property with the intent to rent it out, lenders may factor the rental income into your mortgage application. Long-term rentals : Lenders typically accept 50–80% of the expected rental income when calculating your debt-service ratios. Short-term rentals (Airbnb, VRBO, etc.) : Many traditional lenders are cautious about using projected income from short-term rentals. Alternative lenders may be more flexible, depending on the property’s location and your financial profile. 4. Debt-Service Ratios Lenders use your Gross Debt Service (GDS) and Total Debt Service (TDS) ratios to determine if you can handle the mortgage payments alongside your other obligations. With investment or vacation properties, lenders may apply stricter guidelines, especially if your primary residence already carries a large mortgage. 5. Credit & Financial Stability Your credit score, employment history, and overall financial health still matter. Since vacation and rental properties are considered higher risk, lenders want reassurance that you can handle the additional debt—even if rental income fluctuates or the property sits vacant. 6. Insurance Requirements Rental properties often require specialized landlord insurance, and vacation homes may need coverage tailored to seasonal or secondary use. Lenders will want proof of adequate insurance before releasing mortgage funds. The Bottom Line Buying a vacation property or rental can be exciting, but financing these purchases comes with extra rules and considerations. From higher down payments to stricter property requirements, lenders want to be confident that you can handle the responsibility. If you’re considering a second property, the best step is to work with a mortgage professional who can compare lender requirements, outline your options, and find the financing that works best for you. Thinking about making your dream of a vacation or rental property a reality? Connect with us today.