GDS/TDS Ratios Explained

Jeff Johnson • November 6, 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.

Jeff Johnson

Mortgage Expert

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Getting a Mortgage Shouldn’t Be Stressful—We Can Help

By Jeff Johnson • January 7, 2026
Buying a Home? Follow These 6 Key Steps for a Smooth Experience Buying a home is likely one of the biggest financial decisions you’ll ever make. It’s exciting—but it can also be overwhelming, especially when it comes to understanding how mortgage financing works. To help make the process smoother (and far less stressful), here are six essential steps every homebuyer should follow: 1. Start With a Mortgage Professional—Not MLS It’s tempting to start your home search by scrolling through listings and booking showings—but the real first step should be speaking with an independent mortgage professional . Unlike a bank that offers only one set of products, an independent mortgage expert has access to multiple lenders and options . That means better advice, better rates, and a better chance of finding a mortgage that truly fits your needs. 2. Build a Personalized Mortgage Plan Unless you’re buying your home with cash, you’ll need a solid financing strategy. That means: Reviewing your credit score Running affordability calculations Exploring different mortgage types, terms, and features Understanding down payments and closing costs The sooner you start planning, the more confident you’ll feel. Don’t wait until you’ve found the “perfect” property— get ahead of the process now . 3. Figure Out What You Can Actually Afford What a lender says you can borrow doesn’t always match what you can comfortably pay each month. Take a close look at your budget, lifestyle, and spending habits. Think about how your mortgage payments, property taxes, utilities, and other costs will fit into your everyday cash flow. Avoid the stress of being house-poor by knowing your real-life affordability , not just your paper pre-approval. 4. Get Pre-Approved the Right Way A true mortgage pre-approval isn’t just entering numbers into an online calculator. It means: Completing a mortgage application Submitting all your required documentation Having a mortgage professional fully assess your file When you’re officially pre-approved, you’ll shop for homes with confidence , knowing what you qualify for and that you’re financially ready. 5. Submit Your Documents Promptly and Stay Flexible Once you find a property and your offer is accepted, time is of the essence. That’s when all the upfront work you’ve done really pays off. Be ready to: Provide additional documentation if requested Respond to your mortgage professional quickly Stay flexible and proactive throughout the approval process Your lender needs to verify everything before finalizing the loan, so staying organized is key. 6. Don’t Make Big Financial Changes Before Closing Once you’ve secured financing and waived your conditions, freeze your finances until after you get the keys. Seriously—don’t: Change jobs Apply for new credit Take out a loan Make a large withdrawal Even small changes can throw off your approval. Keep everything status quo until you officially take possession. Recap: 6 Steps to a Smooth Home Purchase Connect with an independent mortgage professional Create a mortgage plan early Know what you can afford (not just what you qualify for) Get fully pre-approved Stay on top of documentation Avoid major financial changes before possession Ready to Buy with Confidence? If you’re thinking about buying a home—or just want to know what’s possible—let’s talk. I’ll help you map out a personalized plan that makes your homebuying journey feel simple, strategic, and stress-free. Reach out anytime. I’d love to help you get started.

How to Get a Mortgage for a Second Property

By Jeff Johnson • December 31, 2025
Thinking About Buying a Second Property? Here’s What to Know Buying a second property is an exciting milestone—but it’s also a big financial decision that deserves thoughtful planning. Whether you're dreaming of a vacation retreat, building a rental portfolio, or looking to support a family member with a place to live, there are plenty of reasons to consider a second home. But before you jump in, it's important to understand the strategy and steps involved. Start with “Why” The best place to begin? Clarify your motivation. Ask yourself: Why do I want to buy a second property? What role will it play in my life or finances? How does this fit into my long-term goals? Whether your focus is lifestyle, income, or legacy planning, knowing your “why” will help you make smarter decisions from the start. Talk to a Mortgage Expert Early Once you’ve nailed down your goals, the next step is to sit down with an independent mortgage professional. Why? Because buying a second property isn't quite the same as buying your first. Even if you’ve qualified before, financing a second home has unique considerations—especially when it comes to down payments, debt ratios, and how lenders assess risk. How Much Do You Need for a Down Payment? Here’s where the purpose of the property really matters: Owner-occupied or family use: You may qualify with as little as 5–10% down, depending on the property and lender. Income property: Expect to put down 20–35%, especially for short-term rentals or if it won’t be occupied by you or a family member. Your down payment amount can be one of the biggest hurdles—but with strategic planning, it’s often manageable. Ways to Fund the Down Payment If you don’t have the full amount in cash, you might be able to tap into your current home’s equity to help fund the purchase. Here are a few ways to do that: ✅ Refinance your existing mortgage to access additional funds ✅ Secure a second mortgage behind your current one ✅ Open a HELOC (Home Equity Line of Credit) ✅ Use a reverse mortgage (in certain age-qualified scenarios) ✅ Take out a new mortgage if your current home is mortgage-free These options depend on your income, credit, home value, and overall financial picture—another reason why having a pro in your corner matters. Second Property Strategy: It’s More Than Just Numbers This purchase should be part of a bigger financial plan—one that balances risk and reward. It’s about: Assessing your full financial health Maximizing your existing assets Minimizing your cost of borrowing Aligning your purchase with your long-term goals Ready to Take the Next Step? There’s no one-size-fits-all answer when it comes to buying a second property. That’s why it helps to talk things through with someone who understands both the big picture and the small details. If you’re ready to explore your options and build a plan to make that second property dream a reality, let’s connect. I’d love to help you take the next step with confidence.