Mortgage rates have finally started easing, and plenty of buyers are rushing back into the market expecting good news at the closing table.
Then their loan officer runs one calculation and the whole thing stalls.
It's their debt-to-income ratio — the unglamorous math that quietly decides who gets a house and who gets a rejection letter.
Lenders add up every monthly debt payment you owe — car loans, student loans, minimum credit card payments, personal loans, child support — and divide it by your gross monthly income before taxes.
If you earn $7,000 a month and owe $2,100 in debt payments, your DTI is 30%.
Most conventional loans want that number at or below 36%, though many lenders will stretch to 43% or even 50% with strong credit and cash reserves.
The problem is that DTI counts the payment on your future mortgage too.
So a buyer who looks perfectly fine on paper — good job, solid credit, no late payments — can blow past the limit once the estimated house payment gets added in.
What's tripping people up right now is the credit card piece.
Average card balances have climbed past $6,000 per household, and minimum payments on those balances can run $150 to $250 a month.
That single line item is enough to push a borderline borrower from approvable to denied, even if they've never missed a payment in their life.
Paying off a small card balance can erase a monthly obligation entirely, because lenders count the minimum payment, not the balance.
Paying down a $2,000 balance to zero might only cost a few hundred dollars a month in cash but can free up $50 or more in DTI room — and that can be the difference between a 43% and a 41% ratio.
Federal student loans on income-driven repayment plans are often counted at a lower payment than the standard 10-year figure, though rules have shifted and lenders don't all calculate it the same way, so ask specifically.
Adding a co-borrower with steady income can lower the ratio fast.
And a larger down payment doesn't change DTI directly, but it shrinks the loan amount and therefore the projected payment.
One more thing that catches people off guard: lenders typically recheck your finances right before closing.
Opening a new credit card for furniture, financing a car, or co-signing a loan for a relative during escrow can sink a deal that was already approved.
The safe move is to freeze every new credit application between offer acceptance and closing day.
If you're planning to buy in the next year, run the math yourself now rather than waiting for a lender to do it.
Add up your minimum payments, divide by your gross monthly pay, and see where you land.
If you're above 36%, you have time to fix it — but you need to know the number before you fall in love with a house. **The takeaway:** DTI is boring, easy to ignore, and one of the few mortgage hurdles you can actually move with a few months of planning.
Buyers who check it early tend to get keys.
Final Thoughts
Buyers who ignore it get a surprise phone call.