Mortgage Approval 101: GDS & TDS Explained

Danielle McIntosh • August 20, 2025

Can You Afford That Mortgage? Let’s Talk About Debt Service Ratios

One of the biggest factors lenders look at when deciding whether you qualify for a mortgage is something called your debt service ratios. It’s a financial check-up to make sure you can handle the payments—not just for your new home, but for everything else you owe as well.


If you’d rather skip the math and have someone walk through this with you, that’s what I’m here for. But if you like to understand how things work behind the scenes, keep reading. We’re going to break down what these ratios are, how to calculate them, and why they matter when it comes to getting approved.


What Are Debt Service Ratios?

Debt service ratios measure your ability to manage your financial obligations based on your income. There are two key ratios lenders care about:

  1. Gross Debt Service (GDS)
    This looks at the percentage of your income that would go toward housing expenses only.

   2. Total Debt Service (TDS)
       This includes your housing costs plus all other debt payments—car loans, credit cards, student loans, support payments, etc.


How to Calculate GDS and TDS

Let’s break down the formulas.


GDS Formula:

(P + I + T + H + Condo Fees*) ÷ Gross Monthly Income


Where:

P = Principal

I = Interest

T = Property Taxes

H = Heat


Condo fees are usually calculated at 50% of the total amount


TDS Formula:

(GDS + Monthly Debt Payments) ÷ Gross Monthly Income


These ratios tell lenders if your budget is already stretched too thin—or if you’ve got room to safely take on a mortgage.


How High Is Too High?


Most lenders follow maximum thresholds, especially for insured (high-ratio) mortgages.

As of now, those limits are typically:

GDS: Max 39%

TDS: Max 44%


Go above those numbers and your application could be declined, regardless of how confident you feel about your ability to manage the payments.


Real-World Example

Let’s say you’re earning $90,000 a year, or $7,500 a month.

You find a home you love, and the monthly housing costs (mortgage payment, property tax, heat) total $1,700/month.


GDS = $1,700 ÷ $7,500 = 22.7%


You’re well under the 39% cap—so far, so good.


Now factor in your other monthly obligations:

  • Car loan: $300
  • Child support: $500
  • Credit card/line of credit payments: $700
    Total other debt = $1,500/month


Now add that to the $1,700 in housing costs:
TDS = $3,200 ÷ $7,500 = 42.7%


Uh oh. Even though your GDS looks great, your TDS is just over the 42% limit. That could put your mortgage approval at risk—even if you’re paying similar or higher rent now.


What Can You Do?

In cases like this, small adjustments can make a big difference:

  • Consolidate or restructure your debts to lower monthly payments
  • Reallocate part of your down payment to reduce high-interest debt
  • Add a co-applicant to increase qualifying income
  • Wait and build savings or credit strength before applying


This is where working with an experienced mortgage professional pays off. We can look at your entire financial picture and help you make strategic moves to qualify confidently.


Don’t Leave It to Chance

Everyone’s situation is different, and debt service ratios aren’t something you want to guess at. The earlier you start the conversation, the more time you’ll have to improve your numbers and boost your chances of approval.


If you're wondering how much home you can afford—or want help analyzing your own GDS and TDS—let’s connect. I’d be happy to walk through your numbers and help you build a solid mortgage strategy.


Danielle McIntosh

Licensed Mortgage Broker

GET STARTED

Let’s Talk About Getting Top Dollar for Your Property

By Danielle McIntosh • May 20, 2026
When it comes to selling your home, most people think the first call should be to a real estate agent. But the smartest first step often isn’t with your agent—it’s with an independent mortgage professional. Why? Because your mortgage plays a bigger role in your bottom line than most people realize. Planning to Buy After You Sell If selling means you’ll also be purchasing another property, you’ll want to know exactly where you stand financially before listing. Mortgage rules change regularly, and qualifying once doesn’t guarantee you’ll qualify again. Getting a pre-approval in place ensures you know what you can afford and eliminates surprises later. On top of that, reviewing the terms of your existing mortgage could uncover options you may not have considered. For example, porting your mortgage instead of arranging a brand-new one could save you thousands. Selling Without Buying Even if you aren’t planning to buy right away, there’s still an important step: understanding the cost of breaking your mortgage. Unless your mortgage is open, penalties apply—and they can be significant. By reviewing the numbers with a mortgage professional, you might find that simply adjusting your timeline could reduce or even avoid costly fees. Navigating Life Changes In situations like a marital breakdown, it can feel like selling the family home is the only path forward. But that’s not always the case. With the right guidance and a legal separation agreement, one spouse may be able to buy out the other, keeping the home and providing stability for everyone involved. The Bottom Line Selling your property is more than just putting a sign on the lawn—it’s about creating a financial plan that protects your equity and positions you for the best possible outcome. Before you take the leap, let’s sit down and review your options. 📞 If you’re ready to talk strategy and make sure you get top dollar for your property, I’d be happy to connect anytime.

Down Payment Options for Canadian Homebuyers

By Danielle McIntosh • May 13, 2026
For most Canadians, the down payment is the biggest hurdle to homeownership. A down payment is the initial amount you contribute toward your property purchase, while the lender covers the rest through a mortgage. By law, Canadian lenders can only finance up to 95% of a property’s value, which means you’ll need at least 5% down to qualify. If you’re putting down less than 20%, your mortgage must be insured through one of Canada’s three default insurance providers— CMHC, Sagen (formerly Genworth), or Canada Guaranty . This insurance comes at a cost, but it can be rolled into your mortgage amount. The less you put down, the higher the premium. Since saving a down payment can feel overwhelming, it helps to know the different sources you can draw from. Here are the most common options available to Canadian homebuyers: 1. Savings & Personal Resources The most straightforward source is your own savings. Lenders will ask to see a 90-day history of the funds in your account. Any large deposits outside of regular payroll must be explained with documentation—such as the sale of a vehicle or a transfer from an investment account. This requirement isn’t just red tape; it’s part of Canada’s anti-money laundering rules. 2. Proceeds from the Sale of a Property If you’ve recently sold another home, you can use the proceeds as a down payment on your new purchase. Proof of the sale—such as the final statement of adjustments from your lawyer—will be required. 3. RRSP Home Buyers’ Plan (HBP) First-time buyers can withdraw up to $35,000 each (or $70,000 as a couple) from their RRSPs to put toward a down payment under the federal Home Buyers’ Plan . The funds are withdrawn tax-free, but they must be repaid over a 15-year period. This is a popular option for buyers who have been steadily contributing to their retirement savings. 4. Gifted Down Payment With today’s housing prices, many buyers turn to family for help. A parent or immediate family member can provide a gift that makes up part—or even all—of the required down payment. The lender will require a signed gift letter confirming that the money is a true gift (with no repayment expected) and proof that the funds have been deposited into your account. 5. Borrowed Down Payment In some cases, you may be able to borrow your down payment. This option is usually available only if you have strong credit and sufficient income. The payments on the borrowed funds are factored into your debt service ratios, so affordability is key. Lenders typically use 3% of the outstanding balance when calculating the additional payment. The Bottom Line A down payment doesn’t have to come from just one source—it can be a combination of savings, gifted funds, RRSPs, or other resources. What matters most is being able to show where the money came from and that it meets lender requirements. If you’d like to explore your options or learn how much you might qualify for, it’s never too early to start the conversation. Connect with us today—we’d be happy to help you create a plan and take the first steps toward homeownership.