Mortgage Approval 101: GDS & TDS Explained

Carla Sturm • 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.


Carla Sturm
GET STARTED

How to Get a Mortgage for a Second Property

By Carla Sturm • January 14, 2026
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.

Is Refinancing Your Mortgage a Good Way to Consolidate Debt?

By Carla Sturm • January 7, 2026
If you're a homeowner juggling multiple debts, you're not alone. Credit cards, car loans, lines of credit—it can feel like you’re paying out in every direction with no end in sight. But what if there was a smarter way to handle it? Good news: there is. And it starts with your home. Use the Equity You’ve Built to Lighten the Load Every mortgage payment you make, every bit your home appreciates—you're building equity. And that equity can be a powerful financial tool. Instead of letting high-interest debts drain your income, you can leverage your home’s equity to combine and simplify what you owe into one manageable, lower-interest payment. What Does That Look Like? This strategy is called debt consolidation , and there are a few ways to do it: Refinance your existing mortgage Access a Home Equity Line of Credit (HELOC) Take out a second mortgage Each option has its own pros and cons, and the right one depends on your situation. That’s where I come in—we’ll look at the numbers together and choose the best path forward. What Can You Consolidate? You can roll most types of consumer debt into your mortgage, including: Credit cards Personal loans Payday loans Car loans Unsecured lines of credit Student loans These types of debts often come with sky-high interest rates. When you consolidate them into a mortgage—secured by your home—you can typically access much lower rates, freeing up cash flow and reducing financial stress. Why This Works Debt consolidation through your mortgage offers: Lower interest rates (often significantly lower than credit cards or payday loans) One simple monthly payment Potential for faster repayment Improved cash flow And if your mortgage allows prepayment privileges—like lump-sum payments or increased monthly payments—those features can help you pay everything off even faster. Smart Strategy, Not Just a Quick Fix This isn’t just about lowering your monthly bills (although that’s a major perk). It’s about restructuring your finances in a way that’s sustainable, efficient, and empowering. Instead of feeling like you're constantly catching up, you can create a plan to move forward with confidence—and even start saving again. Here’s What the Process Looks Like: Review your current debts and cash flow Assess how much equity you’ve built in your home Explore consolidation options that fit your goals Create a personalized plan to streamline your payments and reduce overall costs Ready to Regain Control? If your debts are holding you back and you're ready to use the equity you've worked hard to build, let's talk. There’s no pressure—just a practical conversation about your options and how to move toward a more flexible, debt-free future. Reach out today. I’m here to help you make the most of what you already have.