If you're house hunting this spring, there's a number that matters more than your credit score, and most buyers don't know it exists until a lender says no.
It's your debt-to-income ratio, or DTI, and the rules around it have quietly gotten stricter at several major lenders over the past year.
Add up every monthly debt payment — car loan, student loans, minimum credit card payments, personal loans — then divide by your gross monthly income.
If you earn $6,000 a month and owe $2,400 in total payments, your DTI is 40%.
Conventional loans backed by Fannie Mae and Freddie Mac generally cap that number at 45% to 50%, depending on credit score and savings.
FHA loans have historically allowed up to 57% with compensating factors.
Lenders can and do set their own overlays — internal rules stricter than the federal guidelines.
In a market where home prices are still elevated and mortgage rates hover near 7%, several banks have tightened those overlays.
A borrower who qualified at 49% two years ago might now get flagged at 43%.
Home prices in many metros haven't fallen enough to restore affordability, and wages, while up, haven't kept pace with the full cost of a mortgage, taxes, insurance, and HOA fees.
Rising property insurance premiums in states like Florida and Texas are getting folded into escrow payments, which pushes DTI higher without the buyer spending a dime differently.
There's a second number buyers miss: the front-end ratio.
That's just housing costs divided by income.
Most conventional lenders want it under 28%.
But with today's rates and insurance costs, plenty of otherwise qualified buyers blow past 30% on housing alone — before a single credit card payment is counted.
A buyer with a $95,000 salary and a $450 car payment, $200 in student loans, and a $150 minimum on cards already carries roughly $800 a month in non-housing debt.
At 7% on a 30-year loan, adding a $2,300 mortgage payment puts total DTI near 39%.
That's fine on paper — until the property tax reassessment and insurance quote land.
Lenders and loan servicers prefer lower-risk borrowers, and tighter DTI rules shift the market toward cash-heavy purchasers and people who can pay down debt fast.
That's a structural advantage for higher earners and repeat buyers, and a hurdle for first-timers relying on FHA programs.
Pay down revolving debt first — credit cards carry the highest minimum payments relative to balance.
A $500-a-month card payment kills your DTI; eliminating that balance can free up $15,000 to $20,000 in borrowing power depending on rates.
Avoid financing a car within six months of applying for a mortgage.
And ask your lender for the exact overlay they use, not the agency guideline.
Also worth knowing: some lenders allow "compensating factors" — larger down payments, verified cash reserves, or a long rental history with on-time payments — to offset a high DTI.
The bigger picture is that affordability math has changed for good.
Buyers waiting for rates to drop to 5% may wait a while, and DTI limits don't loosen just because rates fall — they loosen when lender risk appetite returns, which tends to lag.
Our take: DTI is the most under-discussed number in American homebuying, and it's quietly doing more to lock people out than interest rates alone.
Final Thoughts
Understand it before you tour a single house, because by the time a lender runs the math, your options are already narrowed.