Mortgage lenders have quietly tightened the screws in 2025, and the number doing the damage isn't your credit score or your down payment.
It's your debt-to-income ratio, or DTI — and for a growing slice of American households, it's the single figure standing between them and a house.
Lenders add up every monthly debt payment you owe — car loans, student loans, minimum credit card payments, personal loans — and divide it by your gross monthly income.
Most conventional mortgages now want to see 43% or lower, and many lenders start getting nervous above 36%.
Fannie Mae's own data shows the average purchase loan backed in recent years has crept toward the high 30s, leaving millions of buyers with almost no cushion.
The problem is that the denominator — your income — hasn't kept pace with the numerator.
Grocery bills are up roughly 25% since 2019, auto loan payments hit record highs near $740 a month on average, and credit card balances topped $1.2 trillion.
Even borrowers who did everything right on paper are watching their DTI drift upward without taking on a single new loan.
What's catching people off guard is how unforgiving the math has become.
A household earning $7,500 a month gross can carry about $3,225 in total debt payments at a 43% cap.
A $450 car payment, a $300 student loan, and $250 in minimum card payments eats $1,000 before the mortgage even enters the picture.
That leaves roughly $2,200 for housing — which, at today's rates near 6.5%, supports a loan of about $340,000.
In much of the country, that doesn't buy much.
There's a wrinkle many buyers miss: lenders calculate DTI using gross income, not take-home pay.
So a family clearing $5,800 a month after taxes can still qualify on a ratio built from $7,500.
The gap between qualifying and affording has never been wider.
Paying down revolving balances does double duty — it lowers your minimum payments and can lift your credit score.
Asking a loan officer to run a "what-if" scenario before you house-hunt costs nothing and tells you exactly how much you'd need to knock off each debt to cross under the threshold.
Some buyers also qualify for FHA loans, which allow DTIs up to 50% with compensating factors like cash reserves or a strong payment history.
As long as mortgage rates stay elevated and everyday costs keep climbing, DTI will keep functioning as a silent gatekeeper — deciding who gets to buy and who keeps renting.
That's a shift with real consequences for household wealth building over the next decade.
Our take: DTI has become the number Americans ignore until it rejects them.
Treat it like a credit score — check it quarterly, know your target, and attack the smallest balances first.
The buyers who win in this market won't be the ones with the biggest salaries.
Final Thoughts
They'll be the ones who did the arithmetic before the lender did.