Mortgage Approval 101: GDS & TDS Explained

Jeff Johnson • September 10, 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.


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.