Mortgage Approval 101: GDS & TDS Explained

Rabinder Dhillon • September 3, 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.


RABINDER
MORTGAGE BROKER

LET'S CONNECT
By Rabinder Dhillon December 10, 2025
Bank of Canada maintains policy rate at 2.1/4%. FOR IMMEDIATE RELEASE Media Relations Ottawa, Ontario December 10, 2025 The Bank of Canada today held its target for the overnight rate at 2.25%, with the Bank Rate at 2.5% and the deposit rate at 2.20%. Major economies around the world continue to show resilience to US trade protectionism, but uncertainty is still high. In the United States, economic growth is being supported by strong consumption and a surge in AI investment. The US government shutdown caused volatility in quarterly growth and delayed the release of some key economic data. Tariffs are causing some upward pressure on US inflation. In the euro area, economic growth has been stronger than expected, with the services sector showing particular resilience. In China, soft domestic demand, including more weakness in the housing market, is weighing on growth. Global financial conditions, oil prices, and the Canadian dollar are all roughly unchanged since the Bank’s October Monetary Policy Report (MPR). Canada’s economy grew by a surprisingly strong 2.6% in the third quarter, even as final domestic demand was flat. The increase in GDP largely reflected volatility in trade. The Bank expects final domestic demand will grow in the fourth quarter, but with an anticipated decline in net exports, GDP will likely be weak. Growth is forecast to pick up in 2026, although uncertainty remains high and large swings in trade may continue to cause quarterly volatility. Canada’s labour market is showing some signs of improvement. Employment has shown solid gains in the past three months and the unemployment rate declined to 6.5% in November. Nevertheless, job markets in trade-sensitive sectors remain weak and economy-wide hiring intentions continue to be subdued. CPI inflation slowed to 2.2% in October, as gasoline prices fell and food prices rose more slowly. CPI inflation has been close to the 2% target for more than a year, while measures of core inflation remain in the range of 2½% to 3%. The Bank assesses that underlying inflation is still around 2½%. In the near term, CPI inflation is likely to be higher due to the effects of last year’s GST/HST holiday on the prices of some goods and services. Looking through this choppiness, the Bank expects ongoing economic slack to roughly offset cost pressures associated with the reconfiguration of trade, keeping CPI inflation close to the 2% target. If inflation and economic activity evolve broadly in line with the October projection, Governing Council sees the current policy rate at about the right level to keep inflation close to 2% while helping the economy through this period of structural adjustment. Uncertainty remains elevated. If the outlook changes, we are prepared to respond. The Bank is focused on ensuring that Canadians continue to have confidence in price stability through this period of global upheaval. Information note The next scheduled date for announcing the overnight rate target is January 28, 2026. The Bank’s next MPR will be released at the same time.
By Rabinder Dhillon December 3, 2025
How to Use Your Mortgage to Finance Home Renovations Home renovations can be exciting—but they can also be expensive. Whether you're upgrading your kitchen, finishing the basement, or tackling a much-needed repair, the cost of materials and labour adds up quickly. If you don’t have all the cash on hand, don’t worry. There are smart ways to use mortgage financing to fund your renovation plans without derailing your financial stability. Here are three mortgage-related strategies that can help: 1. Refinancing Your Mortgage If you're already a homeowner, one of the most straightforward ways to access funds for renovations is through a mortgage refinance. This involves breaking your current mortgage and replacing it with a new one that includes the amount you need for your renovations. Key benefits: You can access up to 80% of your home’s appraised value , assuming you qualify. It may be possible to lower your interest rate or reduce your monthly payments. Timing tip: If your mortgage is up for renewal soon, refinancing at that time can help you avoid prepayment penalties. Even mid-term refinancing could make financial sense, depending on your existing rate and your renovation goals. 2. Home Equity Line of Credit (HELOC) If you have significant equity in your home, a Home Equity Line of Credit (HELOC) can offer flexible funding for renovations. A HELOC is a revolving credit line secured against your home, typically at a lower interest rate than unsecured borrowing. Why consider a HELOC? You only pay interest on the amount you use. You can access funds as needed, which is ideal for staged or ongoing renovations. You maintain the terms of your existing mortgage if you don’t want to refinance. Unlike a traditional loan, a HELOC allows you to borrow, repay, and borrow again—similar to how a credit card works, but with much lower rates. 3. Purchase Plus Improvements Mortgage If you're in the market for a new home and find a property that needs some work, a "Purchase Plus Improvements" mortgage could be a great option. This allows you to include renovation costs in your initial mortgage. How it works: The renovation funds are advanced based on a quote and are held in trust until the work is complete. The renovations must add value to the property and meet lender requirements. This type of mortgage lets you start with a home that might be more affordable upfront and customize it to your taste—all while building equity from day one. Final Thoughts Your home is likely your biggest investment, and upgrading it wisely can enhance both your comfort and its value. Mortgage financing can be a powerful tool to fund renovations without tapping into high-interest debt. The right solution depends on your unique financial situation, goals, and timing. Let’s chat about your options, run the numbers, and create a plan that works for you. 📞 Ready to renovate? Connect anytime to get started!