Mortgage Approval 101: GDS & TDS Explained

Dean Garrett • October 23, 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.


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Dean Garrett

Mortgage Professional

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Understanding Payment Frequency

By Dean Garrett • October 16, 2025
You’ve most likely heard that there are two certainties in life; death and taxes. Well, as it relates to your mortgage, the single certainty is that you will pay back what you borrow, plus interest. With that said, the frequency of how often you make payments to the lender is somewhat up to you! The following looks at the different types of payment frequencies and how they impact your mortgage. Here are the six payment frequency types Monthly payments – 12 payments per year Semi-Monthly payments – 24 payments per year Bi-weekly payments – 26 payments per year Weekly payments – 52 payments per year Accelerated bi-weekly payments – 26 payments per year Accelerated weekly payments – 52 payments per year Options one through four are straightforward and designed to match your payment frequency with your employer. So if you get paid monthly, it makes sense to arrange your mortgage payments to come out a few days after payday. If you get paid every second Friday, it might make sense to have your mortgage payments match your payday. However, options five and six have that word accelerated before the payment frequency. Accelerated bi-weekly and accelerated weekly payments accelerate how fast you pay down your mortgage. Choosing the accelerated option allows you to lower your overall cost of borrowing on autopilot. Here’s how it works. With the accelerated bi-weekly payment frequency, you make 26 payments in the year. Instead of dividing the total annual payment by 26 payments, you divide the total yearly payment by 24 payments as if you set the payments as semi-monthly. Then you make 26 payments on the bi-weekly frequency at the higher amount. So let’s use a $1000 payment as the example: Monthly payments formula: $1000/1 with 12 payments per year. A payment of $1000 is made once per month for a total of $12,000 paid per year. Semi-monthly formula: $1000/2 with 24 payments per year. A payment of $500 is paid twice per month for a total of $12,000 paid per year. Bi-weekly formula: $1000 x 12 / 26 with 26 payments per year. A payment of $461.54 is made every second week for a total of $12,000 paid per year. Accelerated bi-weekly formula: $1000/2 with 26 payments per year. A payment of $500 is made every second week for a total of $13,000 paid per year. You see, by making the accelerated bi-weekly payments, it’s like you end up making two extra payments each year. By making a higher payment amount, you reduce your mortgage principal, which saves interest on the entire life of your mortgage. The payments for accelerated weekly payments work the same way. It’s just that you’d be making 52 payments a year instead of 26. By choosing an accelerated option for your payment frequency, you lower the overall cost of borrowing by making small extra payments as part of your regular payment schedule. Now, exactly how much you’ll save over the life of your mortgage is hard to nail down. Calculations are hard to do because of the many variables; mortgages come with different amortization periods and terms with varying interest rates along the way. However, an accelerated bi-weekly payment schedule could reduce your amortization by up to three years if maintained throughout the life of your mortgage. If you’d like to look at some of the numbers as they relate to you and your mortgage, please don’t hesitate to connect anytime; it would be a pleasure to work with you.
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Smart Strategies to Save for Your Down Payment

By Dean Garrett • October 9, 2025
How to Start Saving for a Down Payment (Without Overhauling Your Life) Let’s face it—saving money isn’t always easy. Life is expensive, and setting aside extra cash takes discipline and a clear plan. Whether your goal is to buy your first home or make a move to something new, building up a down payment is one of the biggest financial hurdles. The good news? You don’t have to do it alone—and it might be simpler than you think. Step 1: Know Your Numbers Before you can start saving, you need to know where you stand. That means getting clear on two things: how much money you bring in and how much of it is going out. Figure out your monthly income. Use your net (after-tax) income, not your gross. If you’re self-employed or your income fluctuates, take an average over the last few months. Don’t forget to include occasional income like tax returns, bonuses, or government benefits. Track your spending. Go through your last 2–3 months of bank and credit card statements. List out your regular bills (rent, phone, groceries), then your extras (dining out, subscriptions, impulse buys). You might be surprised where your money’s going. This part isn’t always fun—but it’s empowering. You can’t change what you don’t see. Step 2: Create a Plan That Works for You Once you have the full picture, it’s time to make a plan. The basic formula for saving is simple: Spend less than you earn. Save the difference. But in real life, it’s more about small adjustments than major sacrifices. Cut what doesn’t matter. Cancel unused subscriptions or set a dining-out limit. Automate your savings. Set up a separate “down payment” account and auto-transfer money on payday—even if it’s just $50. Find ways to boost your income. Can you pick up a side job, sell unused stuff, or ask for a raise? Consistency matters more than big chunks. Start small and build momentum. Step 3: Think Bigger Than Just Saving A lot of people assume saving for a down payment is the first—and only—step toward buying a home. But there’s more to it. When you apply for a mortgage, lenders look at: Your income Your debt Your credit score Your down payment That means even while you’re saving, you can (and should) be doing things like: Building your credit score Paying down high-interest debt Gathering documents for pre-approval That’s where we come in. Step 4: Get Advice Early Saving up for a home doesn’t have to be a solo mission. In fact, talking to a mortgage professional early in the process can help you avoid missteps and reach your goal faster. We can: Help you calculate how much you actually need to save Offer tips to strengthen your application while you save Explore alternate down payment options (like gifts or programs for first-time buyers) Build a step-by-step plan to get you mortgage-ready Ready to get serious about buying a home? We’d love to help you build a plan that fits your life—and your goals. Reach out anytime for a no-pressure conversation.