Mortgage lenders have a number for you, and it's not your credit score.
It's your debt-to-income ratio, or DTI—the share of your monthly gross income that goes toward debt payments.
And in 2025, that single figure is quietly deciding who gets to buy a home and who gets told to keep renting.
Add up your minimum monthly payments: car loan, student loans, credit cards, personal loans, plus the projected mortgage payment on the house you want.
Divide that by your gross monthly income before taxes.
Then it crept to 43%, the threshold where most qualified mortgages stop being "qualified." Now some conventional loans let buyers push toward 50% with compensating factors like hefty cash reserves.
Fannie Mae's own data has shown a growing share of purchase loans landing above 45% DTI in recent years.
The catch is what happens on the back end.
A high DTI doesn't just shrink your approval odds—it can raise your rate, force mortgage insurance, or push you into a pricier loan product.
Lenders price risk, and stretched borrowers are riskier.
That's not a moral judgment; it's just math.
Where it gets ugly is the student loan problem.
Some borrowers on income-driven repayment plans have been reporting payments that don't match what lenders calculate.
Federal guidelines now generally require lenders to use the actual payment for IDR plans rather than a percentage of the balance—but servicer confusion has caused denials.
If you're house-hunting with student debt, get a written mortgage payment quote in advance and ask how your specific repayment plan is being counted.
The minimum payment on a $10,000 balance might be $250.
That $250 counts against your DTI every single month, even if you pay it off in full.
Paying down revolving debt before applying is one of the few levers you fully control.
There's a legitimate debate about whether DTI is even the right tool.
It ignores your actual savings rate, your emergency fund, and whether your rent is about to end.
A household with a 40% DTI and two years of expenses saved is arguably safer than one at 35% with nothing in the bank.
Lenders know this—they're just not set up to underwrite your personality.
What nobody selling you a house will say out loud: the 43% ceiling exists partly because of post-2008 regulations designed to prevent the exact blowup that wrecked the economy.
DTI is a blunt instrument born from a real disaster.
Pull your credit report, list every minimum payment, and run the math at today's rates—not last year's.
If you're above 45%, focus on the debt with the highest payment-to-balance ratio, usually credit cards.
And get pre-approved early enough to fix problems before you fall in love with a house.
The uncomfortable truth is that housing affordability in many metros has less to do with your DTI and more to do with supply, zoning, and rates the Fed controls.
Final Thoughts
Your ratio is just the scorecard you get judged on.