Last updated October 13, 2026
Your lender's approval number and your real affordability number are not the same thing. What the math actually looks like across St. Louis price points -- and what lenders will not tell you.
Payments use the site-wide assumptions: a 7.00% rate, 5% down, taxes of 1.12% and insurance of 1% of the price, and 0.60% PMI. See the table ↓
To keep the whole payment at a comfortable 28% of gross income, roughly $55,000 a year for a $150,000 home, $92,000 for $250,000 and $110,000 for $300,000, at a 7% rate with 5% down. Lenders may approve you on much less, which isn’t the same as being able to afford it. See the full table ↓
About $73,400 a year to keep the payment at 28% of gross income, at a 7% rate with 5% down. A lender could approve it on about $47,800 if you have no other debts, but that’s a ceiling, not a comfortable budget.
Because a pre-approval measures the most you can borrow, not the payment you can live with. Lenders calculate your maximum loan amount based on your debt-to-income ratio (DTI) -- total monthly debts generally can’t exceed roughly 43% to 50% of your gross monthly income, depending on the loan. They use gross income, not take-home pay, and they may estimate property taxes before you’ve picked the house. Pre-Approved vs. Actually Affordable ↓
For most loans, total monthly debts, including the new housing payment, of about 43% of gross income or less, and up to 50% on many conventional loans approved through automated underwriting. FHA can go higher with compensating factors. Those are maximums, not targets: the 28% housing guideline in the table is the conservative number, and lenders will often approve buyers below it. Debt-to-Income in Practice ↓
Because a pre-approval measures the most you can borrow, not the payment you can live with. Lenders calculate your maximum loan amount based on your debt-to-income ratio (DTI) -- total monthly debts generally can’t exceed roughly 43% to 50% of your gross monthly income, depending on the loan. They use gross income, not take-home pay, and they may estimate property taxes before you’ve picked the house.
The result is a pre-approval number that represents the maximum you can borrow -- not the payment you can sustain comfortably over 30 years in a specific St. Louis neighborhood.
These use the same assumptions as the site’s salary pages and loan calculator: a 7.00% 30-year fixed rate, 5% down, property taxes of 1.12% of the price, homeowners insurance of 1% of the price and PMI of 0.60%. “Comfortable” keeps the whole payment at 28% of gross income; “lender maximum” is 43% total debt-to-income with no other debts. Actual requirements vary by lender, loan type and address.
| Home Price | Down (5%) | Monthly Payment (est.) | Comfortable Income (28%) | Lender Maximum (43%, no other debts) |
|---|---|---|---|---|
| $150,000 | $7,500 | $1,280 | $55,000/yr | $35,800/yr |
| $200,000 | $10,000 | $1,710 | $73,400/yr | $47,800/yr |
| $250,000 | $12,500 | $2,140 | $91,800/yr | $59,700/yr |
| $300,000 | $15,000 | $2,570 | $110,100/yr | $71,700/yr |
| $350,000 | $17,500 | $3,000 | $128,400/yr | $83,600/yr |
| $400,000 | $20,000 | $3,420 | $146,800/yr | $95,600/yr |
For most loans, total monthly debts, including the new housing payment, of about 43% of gross income or less, and up to 50% on many conventional loans approved through automated underwriting. FHA can go higher with compensating factors. Those are maximums, not targets: the 28% housing guideline in the table is the conservative number, and lenders will often approve buyers below it.
The question is not what the lender will approve. The question is what you can actually sustain when a $6,000 HVAC replacement comes up in year 3, or when a job disruption creates a few months of financial pressure. Being approved for the maximum and buying the maximum are two very different decisions.
The costs of owning that aren’t debts: maintenance, utilities and the real tax bill on the specific house.
Yes, but both debt loads count too. If you are buying with a partner, both incomes count toward qualifying. A household where Partner A earns $55,000 and Partner B earns $45,000 has $100,000 combined gross income and qualifies at a significantly higher price point than either individually. However, if Partner B has $600/month in student loan payments, that reduces the available DTI cushion for housing costs.
Run the math as a household, not individually, and include all recurring debts: car payments, student loans, minimum credit card payments, personal loans.
Stress-test it. The right question is not “what is the maximum I can be approved for?” It is "what monthly payment can I sustain for 30 years across different life scenarios?" Run the numbers with a 10% income reduction, a major unexpected repair, and a new car payment. If the housing payment is still manageable in those scenarios, you have found your real number -- not your maximum approval.
Once you know that number, the complete St. Louis home-buying guide walks through what happens next, stage by stage.
What the pre-approval letter actually means -- and what it does not. Mortgage Pre-Approval in St. Louis → → True monthly cost including real tax rates by St. Louis zip code. St. Louis Affordability by Zip Code → → Once you know your number -- how to search without being tracked and sold. How to Use Zillow Without Getting Used → →Know your number? Take it to the showing. My walk-through tool flags repairs room by room and totals the 2026 expected costs, so you can see whether a house still fits your budget once you add what it needs. Save or email your results to compare houses.
Budgeting beyond the lender
The costs of owning that aren’t debts: maintenance, utilities and the real tax bill on the specific house. What Lenders Leave Out ↑
Stress-test it. The right question is not “what is the maximum I can be approved for?” It is "what monthly payment can I sustain for 30 years across different life scenarios?" Run the numbers with a 10% income reduction, a major unexpected repair, and a new car payment. If the housing payment is still manageable in those scenarios, you have found your real number -- not your maximum approval. Finding Your Real Number ↑
Household income
Yes, but both debt loads count too. If you are buying with a partner, both incomes count toward qualifying. A household where Partner A earns $55,000 and Partner B earns $45,000 has $100,000 combined gross income and qualifies at a significantly higher price point than either individually. However, if Partner B has $600/month in student loan payments, that reduces the available DTI cushion for housing costs. Two Incomes, Two Debt Loads ↑
How lenders count income and debt
Gross. Lenders qualify you on income before taxes and deductions, which is one reason an approval can feel bigger than your budget. Build your own budget on take-home pay.
Your documented monthly payment counts. If the payment shows as $0 or the loan is deferred, FHA counts 0.5% of the balance each month instead, so a $40,000 balance counts as $200. Conventional rules vary by agency, so get a statement from your servicer showing your actual payment before you apply.
About 1% of the home’s value a year, or roughly $208 a month on a $250,000 house. Lenders don’t count it, and older St. Louis houses often need more.
This is one piece of the St. Louis home buying process. See how it all fits together:
📚 Complete St. Louis Buyer Guide →
Grew up in South St. Louis, lived in Dogtown for 6 years, now in South County. You'll find us at Wellspring on Lindbergh on Sundays. I'm not selling you a house — I'm showing you how to think about buying or selling a house.
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