Mortgage Approval 101: GDS & TDS Explained

Sarah Hainsworth • 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.


Sarah Hainsworth
GET STARTED

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

By Sarah Hainsworth • December 31, 2025
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.

What Is a Cashback Mortgage and How Does It Work?

By Sarah Hainsworth • December 24, 2025
Cashback Mortgages: Are They Worth It? Here’s What You Need to Know If you’ve been exploring mortgage options and come across the term cashback mortgage , you might be wondering what exactly it means—and whether it’s a smart move. Let’s break it down in simple terms. What Is a Cashback Mortgage? A cashback mortgage is just like a regular mortgage—but with one extra feature: you receive a lump sum of cash when the mortgage closes . This cash is typically: A fixed amount , or A percentage of the total mortgage , usually between 1% and 7% , depending on your mortgage term and lender. The money is tax-free and paid directly to you on closing day. What Can You Use the Cashback For? There are no restrictions on how you use the funds. Here are some common uses: Covering closing costs Buying new furniture Renovations or home upgrades Paying off high-interest debt Boosting your cashflow during a tight transition Whether it’s to help you settle in or catch up financially, cashback can offer a helpful buffer— but it comes at a cost . The True Cost of a Cashback Mortgage Here’s the part many people overlook: cashback mortgages come with higher interest rates than standard mortgages. Why? Because the lender is essentially advancing you a small loan upfront—and they’re going to make that money back (and then some) through your mortgage payments. So while the upfront cash feels like a bonus, you’ll pay more in interest over time to have that convenience. Breaking Down the Numbers It’s hard to give a blanket answer about how much more you’ll pay since it depends on: Your interest rate The cashback amount The mortgage term Your payment schedule This is why it’s important to run the numbers with a mortgage professional who can help you compare this option with others based on your personal financial situation. Are You Eligible for a Cashback Mortgage? Not everyone qualifies. Cashback mortgages generally come with stricter requirements . Lenders often want to see: Excellent credit history Strong, stable income Low debt-to-income ratio If your mortgage file includes anything “outside the box”—like being self-employed or recently changing jobs—qualifying for a cashback mortgage might be tough. What If You Need to Break the Mortgage? This is one of the biggest risks with cashback mortgages. If your circumstances change and you need to break your mortgage early, you could be on the hook for: Paying back some or all of the cashback you received, and A prepayment penalty (typically the interest rate differential or 3 months’ interest—whichever is higher) That can be a very expensive combination. So if there’s even a chance you might need to sell, refinance, or move before your term is up, a cashback mortgage might not be the best fit. Should You Consider a Cashback Mortgage? Maybe—but only with eyes wide open. Cashback mortgages can be helpful in the right scenario, but they’re not free money. They’re a lending tool that benefits the lender , and the key is knowing exactly what you’re agreeing to. Final Thoughts: Talk to an Expert First Choosing the right mortgage isn’t just about the lowest rate or the biggest perk—it’s about making a choice that fits your whole financial picture. If you’re considering a cashback mortgage, or just want to explore all your options, let’s talk. As an independent mortgage professional , I can help you weigh the pros and cons of various products, so you can make a confident, informed decision. Have questions? I’d be happy to help—reach out anytime.