GDS/TDS Ratios Explained

Candice Liberatore • August 7, 2024

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.


Candice Liberatore

Mortgage Financing For Home Renos

By Candice Liberatore • July 16, 2025
If you’re looking to do some home renovations but don’t have all the cash up front to pay for materials and contractors, here are a few ways to use mortgage financing to bring everything together. Existing Home Owners - Mortgage Refinance Probably the most straightforward solution, if you’re an existing homeowner, would be to access home equity through a mortgage refinance. Depending on the terms of your existing mortgage, a mid-term mortgage refinance might make good financial sense; there’s even a chance of lowering your overall cost of borrowing while adding the cost of the renovations to your mortgage. As your financial situation is unique, it never hurts to have the conversation, run the numbers, and look at your options. Let’s talk! If you're not in a huge rush, it might be worth waiting until your existing term is up for renewal. This is a great time to refinance as you won’t incur a penalty to break your existing mortgage. Now, regardless of when you refinance, mid-term or at renewal, you’re able to access up to 80% of the appraised value of your home, assuming you qualify for the increased mortgage amount. Home Equity Line of Credit Instead of talking with a bank about an unsecured line of credit, if you have significant home equity, a home equity line of credit (HELOC) could be a better option for you. An unsecured line of credit usually comes with a pretty high rate. In contrast, a HELOC uses your home as collateral, allowing the lender to give you considerably more favourable terms. There are several different ways to use a HELOC, so if you’d like to talk more about what this could look like for you, connect anytime! Buying a Property - Purchase Plus Improvements If you’re looking to purchase a property that could use some work, some lenders will allow you to add extra money to your mortgage to cover the cost of renovations. This is called a purchase plus improvements. The key thing to keep in mind is that the renovations must increase the value of the property. There is a process to follow and a lot of details to go over, but we can do this together. So if you’d like to discuss using your mortgage to cover the cost of renovating your home, please connect anytime!

Buying a Vacation Home? Here’s What You Need to Know

By Candice Liberatore • July 15, 2025
The idea of owning a vacation home—your own cozy escape from everyday life—is a dream many Canadians share. Whether it’s a lakeside cabin, a ski chalet, or a beachside bungalow, a second property can add lifestyle value, rental income, and long-term wealth. But before you jump into vacation home ownership, it’s important to think through the details—both financial and practical. Start With Your 5- and 10-Year Plan Before you get swept away by the perfect view or your dream destination, take a step back and ask yourself: Will you use it enough to justify the cost? Are there other financial goals that take priority right now? What’s the opportunity cost of tying up your money in a second home? Owning a vacation home can be incredibly rewarding, but it should fit comfortably within your long-term financial goals—not compete with them. Financing a Vacation Property: What to Consider If you don’t plan to pay cash, then financing your vacation home will be your next major step. Mortgage rules for second properties are more complex than those for your primary residence, so here’s what to think about: 1. Do You Have Enough for a Down Payment? Depending on the type of property and how you plan to use it, down payment requirements typically range from 5% to 20%+ . Factors like whether the property is winterized, the purchase price, and its location all come into play. 2. Can You Afford the Additional Debt? Lenders will calculate your Gross Debt Service (GDS) and Total Debt Service (TDS) ratios to assess whether you can take on a second mortgage. GDS: Should not exceed 39% of your income TDS: Should not exceed 44% If you’re not sure how to calculate these, that’s where I can help! 3. Is the Property Mortgage-Eligible? Remote or non-winterized properties, or those located outside of Canada, may not qualify for traditional mortgage financing. In these cases, we may need to look at creative lending solutions . 4. Owner-Occupied or Investment Property? Whether you’ll live in the home occasionally, rent it out, or use it strictly as an investment affects what type of financing you’ll need and what your tax implications might be. Location, Location… Logistics Choosing the right vacation property is more than just finding a beautiful setting. Consider: Current and future development in the area Available municipal services (sewer, water, road maintenance) Transportation access – how easy is it to get to your vacation home in all seasons? Resale value and long-term potential Seasonal access or weather challenges What Happens When You’re Not There? Unless you plan to live there full-time, you'll need to consider: Will you rent it out for extra income? Will you hire a property manager or rely on family/friends? What’s required to maintain valid home insurance while it’s vacant? Planning ahead will protect your investment and give you peace of mind while you’re away. Not Sure Where to Start? I’ve Got You Covered. Buying a vacation home is exciting—but it can also be complicated. As a mortgage broker, I can help you: Understand your financial readiness Calculate your GDS/TDS ratios Review down payment and lending requirements Explore creative solutions like second mortgages , reverse mortgages , or alternative lenders Whether you’re just starting to dream or ready to take action, let’s build a plan that gets you one step closer to your ideal getaway. Reach out today—it would be a pleasure to work with you.