GDS/TDS Ratios Explained

Cynthia Dreger • December 27, 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.

CYNTHIA DREGER

Mortgages Aren’t One-Size-Fits-All

By Cynthia Dreger • August 13, 2025
Why the Cheapest Mortgage Isn’t Always the Smartest Move Some things are fine to buy on the cheap. Generic cereal? Sure. Basic airline seat? No problem. A car with roll-down windows? If it gets you where you're going, great. But when it comes to choosing a mortgage? That’s not the time to cut corners. A “no-frills” mortgage might sound appealing with its rock-bottom interest rate, but what’s stripped away to get you that rate can end up costing you far more in the long run. These mortgages often come with severe limitations—restrictions that could hit your wallet hard if life throws you a curveball. Let’s break it down. A typical no-frills mortgage might offer a slightly lower interest rate—maybe 0.10% to 0.20% less. That could save you a few hundred dollars over a few years. But that small upfront saving comes at the cost of flexibility: Breaking your mortgage early? Expect a massive penalty. Want to make extra payments? Often not allowed—or severely restricted. Need to move and take your mortgage with you? Not likely. Thinking about refinancing? Good luck doing that without a financial hit. Most people don’t plan on breaking their mortgage early—but roughly two-thirds of Canadians do, often due to job changes, separations, relocations, or expanding families. That’s why flexibility matters. So why do lenders even offer no-frills mortgages? Because they know the stats. And they know many borrowers chase the lowest rate without asking what’s behind it. Some banks count on that. Their job is to maximize profits. Ours? To help you make an informed, strategic choice. As independent mortgage professionals, we work for you—not a single lender. That means we can compare multiple products from various financial institutions to find the one that actually suits your goals and protects your long-term financial health. Bottom line: Don’t let a shiny low rate distract you from what really matters. A mortgage should fit your life—not the other way around. Have questions? Want to look at your options? I’d be happy to help. Let’s chat.

What is a Cashback Mortgage?

By Cynthia Dreger • August 6, 2025
As the name implies, a cashback mortgage is similar to a standard mortgage, except that you receive a lump sum of cash upon closing. This lump sum will either be a fixed amount of money or a percentage of the mortgage amount, usually between 1-7%, depending on the mortgage term selected. How you use the cash is entirely up to you. Some of the most common reasons to secure a cashback mortgage are to: Cover closing costs. Buy new furniture. Renovate your property. Supplement cashflow. Consolidate higher-interest debt. Really, you can use the cash for anything you like. It’s tax-free and paid to you directly once the mortgage closes. Understanding the cost of a cashback mortgage. Now, while it might appear like a cashback mortgage is a great way to get some free money, it’s not. Banks aren’t altruistic; they’re in the business of making money by lending money. Securing a mortgage that provides you with cash back at closing will cost you a higher interest rate over your mortgage term. A cashback mortgage is like getting a fixed loan rolled into your mortgage. Your interest rate is increased to cover the additional funds being lent. Now, with so many different cashback options available and with interest rates constantly changing, it's nearly impossible to run through specific calculations on a simple article to outline how much more you’d pay over the term. So, if you'd like to identify the true cost of securing a cashback mortgage, the best place to start is to discuss your financial situation with an independent mortgage professional. When you work with an independent mortgage professional instead of a single bank, you receive unbiased advice, more financing options, and a clear picture of the cost associated with securing a mortgage. Getting cashback at closing is a mortgage feature that makes the bank more money at your expense. This isn’t necessarily a bad thing; the key is to be informed of the costs involved so you can make a good decision. Eligibility for a cashback mortgage. Simply put, a cashback mortgage isn’t for everyone. This is a mortgage product that has tougher qualifications than standard mortgage financing. Any lender willing to offer a cashback mortgage will want to see that you have stable employment, a fabulous credit score, and healthy debt service ratios. If your mortgage application is in any way “unique,” the chances of qualifying for a cashback mortgage are pretty slim. Breaking your mortgage term early. In addition to paying a higher interest rate to cover the cost of receiving the cashback at closing, a cashback mortgage also limits your options down the line. If your life circumstances change and you need to break your mortgage mid-term, depending on the conditions set out in your mortgage contract, you’ll most likely be required to either pay all of the cashback received or at least a portion, depending on how long you’ve had the mortgage. As all cashback mortgages are tied to fixed-rate terms, so in addition to repaying the cashback, you’d also be required to pay the interest rate differential penalty; or 3 months interest, whichever is greater for breaking your mortgage term early. Sufficed to say, should you need to pay out your mortgage early, breaking your cashback mortgage will be costly. Certainly, this is something to consider when assessing the suitability of this mortgage product. Get independent mortgage advice. Understanding the intricacies of mortgage financing can be difficult at the best of times. With all the different terms, rates, and mortgage products available, it’s hard to know which mortgage is best for you. So while a mortgage that offers a cash incentive upon closing might initially seem like an attractive offer, make sure you seek out the guidance of an independent mortgage professional to help you navigate the costs associated with a cashback mortgage. While it might be a great option for you, there might be other mortgage options that better suit your needs. It's worth a conversation for sure! If you’d like to discuss what a cashback mortgage or any other mortgage product would look like for you, please get in touch. It would be a pleasure to work with you.