GDS/TDS Ratios Explained

Shawn Johnson • June 12, 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.

Shawn Johnson

Senior Mortgage Specialist

What Older Canadians Should Know About Mortgage Financing

By Shawn Johnson • April 8, 2026
Retirement doesn’t always mean a mortgage-free life anymore. And that’s okay. Between higher home prices, rising living costs, and longer life expectancy, many Canadians are choosing to retire with a mortgage or refinance later in life to create more flexibility. The goal isn’t perfection. It’s having options that actually support the life you want to live. If you’re thinking about how a mortgage fits into your retirement years, you’re not alone—and you’re not out of options. Why work with an independent mortgage professional? Because retirement financing is not one-size-fits-all. Unlike a single bank, an independent mortgage professional can look across multiple lenders and solutions to find what truly fits your income, equity, and long-term plans—not just what one institution offers. Mortgage options available in retirement Traditional Mortgage Solutions Many retirees still qualify for standard mortgages. Pension income, investment income, and other retirement sources can often be used to support an application. If you have good equity and solid credit, this is often the lowest-cost option. Reverse Mortgages For homeowners 55+, a reverse mortgage can unlock tax-free equity from your home with no monthly payments required. There’s no income verification or medical questions, making it a helpful option for those who want to improve cash flow while staying in their home. Home Equity Line of Credit (HELOC) A HELOC allows you to access your home equity as needed and only pay interest on what you use. Many retirees appreciate the flexibility and like consolidating income and expenses in one place. Private Financing Sometimes life throws a curveball. If timing, income, or credit create challenges, private financing can act as a short-term bridge. It’s not usually the first choice, but it can provide solutions when traditional lenders can’t. If you’re approaching retirement—or already there—and wondering how your mortgage fits into the picture, let’s talk. A clear plan can make retirement feel a lot more secure and a lot less stressful.

How to Qualify for a Mortgage After Bankruptcy in Canada

By Shawn Johnson • April 1, 2026
Financial setbacks happen. Bankruptcies and consumer proposals are more common than most people realize—and they don’t define your future. Going through one doesn’t mean homeownership is off the table forever. It simply means lenders want to see that you’ve taken control, learned from the past, and built a stronger financial foundation moving forward. What lenders look at after a bankruptcy or consumer proposal How long it’s been since your discharge Your discharge date matters. For lenders, this is your reset point. There’s no law that says you must wait a specific amount of time before applying for a mortgage, but the longer your track record after discharge, the stronger your application becomes. What matters most is how responsibly you’ve managed your finances since then. Your credit rebuild Re-establishing credit is critical. After discharge, most people start with a secured credit card and use it consistently and responsibly. To be considered fully re-established, lenders typically want to see: Two active trade lines At least two years of clean payment history Credit limits of around $2,500 on each No late or missed payments Your down payment or equity The more money you can put down—or the more equity you have when refinancing—the lower the risk for the lender. A stronger down payment often opens the door to better terms and more lender options. Your debt service ratios Lenders will also look closely at how much of your income goes toward housing and other debts. The stronger your income relative to your monthly obligations, the easier it is to qualify. Conventional vs. insured mortgage options To access the most competitive mortgage products, lenders typically want to see: At least two years plus one day since discharge Fully re-established credit Minimum down payment requirements met Mortgage insurance in place if your down payment is under 20% (through CMHC, Sagen, or Canada Guaranty) Total debt obligations generally not exceeding 44% of your gross income Alternative lending options Not every situation fits neatly into a bank’s box—and that’s where alternative lending can help. Independent mortgage professionals work with both traditional and alternative lenders, including those who specialize in complex financial situations. These lenders look at the full picture: equity, income stability, and your plan moving forward. While rates and terms may not be as competitive as prime lending, alternative financing can be an effective short-term solution—especially if you need a mortgage before your credit is fully rebuilt. Let’s talk about your next step Whether you’re planning ahead for the best possible mortgage—or need a solution sooner rather than later—there are options available. If you’d like help mapping out a clear path forward, reach out anytime. I’d be happy to review your situation and help you build a plan that gets you back into homeownership with confidence.