Mortgage rates get all the attention, but there's a quieter number that can sink a home loan application before a lender ever looks at your credit score.
It's called your debt-to-income ratio, or DTI, and it's become one of the biggest hurdles for American buyers in 2024 and 2025.
Lenders add up your minimum monthly debt payments — car loans, student loans, credit card minimums, personal loans, and any new mortgage payment — then divide that total by your gross monthly income.
If you earn $6,000 a month and your debts plus the proposed housing payment hit $2,700, your DTI is 45%.
Most conventional lenders prefer a DTI at or below 36%, though many will stretch to 43% and sometimes higher with compensating factors like a big down payment or hefty cash reserves.
FHA loans are often more forgiving, but even those typically cap out around 43% to 50% depending on the lender and your credit profile.
Why is this tripping up so many buyers right now?
First, home prices and mortgage rates are both elevated, so the projected housing payment is bigger than it used to be.
Americans are carrying record credit card balances, and auto loan payments have climbed sharply.
That combination pushes DTI upward even when a buyer's income looks solid on paper.
The tricky part is that DTI isn't just about the house.
A $400 car payment or a $150 credit card minimum can be the difference between approval and denial.
Lenders count the minimum payment on revolving debt, not your actual balance, so paying down a card to zero — or close to it — can shrink your DTI quickly.
If you're house hunting, a few moves can help.
Paying off or paying down high-minimum debts before you apply is the fastest lever.
Avoiding new car loans, furniture financing, or store cards during the mortgage process matters too, since a fresh inquiry and a new payment can move your ratio overnight.
Some buyers also use a co-borrower's income to lower the combined ratio, though that adds its own complications.
It also helps to know your number before a lender tells you.
Add up your minimum monthly debt payments, estimate the housing payment you're targeting, and divide by your gross monthly income.
If the result lands above 43%, you likely need to either reduce debt, increase documented income, or shop in a lower price range.
One more wrinkle: lenders calculate DTI using gross income, before taxes and deductions.
That means your take-home pay can feel much tighter than the ratio suggests, especially with rising insurance, taxes, and HOA fees baked into a monthly payment.
Your credit score gets the headlines, but DTI is often the gatekeeper.
Knowing where you stand — and fixing it before you apply — can save you a rejection, a higher rate, or a stressful scramble later.
Our take: DTI is boring, unglamorous, and arguably more important than the rate quote you're chasing.
Spend an hour calculating yours before you tour a single house.
Final Thoughts
It's free, it's fast, and it might be the most valuable thing you do in your homebuying journey.