If you're shopping for a home this spring, there's a decent chance the math you ran last year no longer works.
Not because rates moved dramatically, but because lenders have gotten pickier about a single figure buried in your application: your debt-to-income ratio, or DTI.
Your DTI is all your monthly debt payments—car loan, student loans, minimum credit card payments, plus the new mortgage you're asking for—divided by your gross monthly income.
If you bring in $8,000 a month and owe $3,200 across everything including the house, your DTI is 40%.
For years, many conventional loans sailed through at 43% to 45%, and some government-backed loans pushed past 50%.
Lately, lenders have been shading those numbers down, especially for buyers with smaller down payments or thinner credit files.
A 44% that got approved in 2022 might come back as a counteroffer today.
Delinquencies on auto loans and credit cards have climbed from their pandemic lows, and mortgage giants Fannie Mae and Freddie Mac have been tightening their automated underwriting engines.
Translation: the software that spits out "approve" or "refer" is asking harder questions.
What this means in practice is that your car payment matters more than you think.
A $650 truck payment eats roughly $650 of your borrowing capacity every month for the life of that loan, and it can knock tens of thousands off the home price you qualify for.
Paying off a $4,000 credit card balance might do more for your home budget than saving another $4,000 for a down payment.
A few practical moves if you're house hunting right now.
First, get a real pre-approval, not a pre-qualification—the kind where a human actually reviews your documents.
Second, pay down revolving debt before you apply, not after.
Third, don't finance a new car, furniture, or appliances in the months before closing; lenders re-pull your credit, and new debt can unravel an approval.
Also worth knowing: DTI isn't the only gate.
Lenders pair it with credit score and cash reserves.
A 42% DTI with a 780 score and six months of savings is a much easier yes than the same 42% with a 660 score and $900 in the bank.
Mostly the lenders and investors who hold the risk, and arguably buyers who avoid stretching into a payment they can't sustain.
First-time buyers and anyone in an expensive metro where prices already outrun local incomes.
It's also a quiet gift to the rental market, since people who can't qualify keep renting—which keeps rent demand, and rents, elevated.
The honest takeaway is that the goalposts moved, and a lot of online affordability calculators haven't caught up.
If a website says you can afford $450,000, treat that as a starting point for a conversation with a loan officer, not a promise.
My view: DTI limits are a blunt instrument that punishes people for old debt rather than current habits, and they hit younger buyers hardest.
Final Thoughts
But until underwriting loosens, the smartest move is to attack your smallest debts first and get pre-approved early—before you fall in love with a house you can't finance.