Mortgage rates have cooled from their 2023 peaks, but plenty of buyers are still getting turned down for a reason that has nothing to do with their credit score.
It's called the debt-to-income ratio, or DTI, and it has quietly become the single biggest hurdle in the homebuying process for middle-income Americans.
Lenders add up every monthly debt payment you owe — car loans, student loans, minimum credit card payments, personal loans — and divide that total by your gross monthly income.
If you earn $7,000 a month and owe $2,100 in debt payments, your DTI is 30%.
The magic number most conventional lenders want to see is 36% or lower.
Go above 43%, and you'll struggle to qualify for a standard qualified mortgage.
Some government-backed loans, like FHA mortgages, allow DTIs up to around 50% with compensating factors, but that's the exception, not the rule.
What trips people up is that DTI counts the home payment you're applying for, not just your existing debts.
So a buyer with a 20% DTI from a car loan and credit cards could still blow past the limit once a $2,200 mortgage payment gets added to the equation.
That's why pre-approval letters often come back smaller than buyers expect.
Lenders have also gotten pickier about what counts as debt.
Federal student loans on income-driven repayment plans are typically calculated using 1% of the balance, not the actual payment — a rule that has blindsided borrowers who thought their $50 monthly payment would be counted as-is.
The good news: DTI is one of the few mortgage metrics you can actually move in a reasonable timeframe.
Paying off a small car loan or knocking out a credit card balance can shave several points off your ratio in a single month.
Increasing your down payment reduces the loan amount and the monthly payment, which lowers DTI from the other direction.
A few practical moves if you're shopping this year: - Get a copy of your credit report and list every recurring debt payment, including buy-now-pay-later plans that report to bureaus. - Ask lenders about their DTI cutoff before you fall in love with a house.
It varies by loan type and lender. - Avoid financing a car or furniture on credit in the six months before applying.
New debt is the fastest way to sink a ratio. - If you're close to the line, a co-borrower with low debt and steady income can change the math entirely.
One more wrinkle: rising property taxes and insurance premiums are pushing monthly housing payments higher in many markets, which means the same house that penciled out last spring might not today.
Buyers should ask lenders to run numbers with a cushion for escrow increases.
The bottom line is that your credit score gets you in the door, but your DTI decides how much house you can actually buy.
In a market where affordability is stretched thin, that ratio is doing more to shape who gets a mortgage than almost anything else. **Our take:** DTI deserves more attention than it gets.
Most buyers obsess over credit scores and down payments while ignoring the one number that quietly caps their budget.
Final Thoughts
If you're planning to buy within a year, start trimming monthly debt now — it's the cheapest mortgage advice you'll get.