Mortgage lenders have quietly tightened the math that decides who gets a home loan, and the number most likely to sink your application isn't your credit score.
It's your debt-to-income ratio, or DTI — the share of your monthly gross income that goes toward debt payments.
With the average 30-year fixed rate hovering near 6.5% and home prices still elevated in most metros, buyers are borrowing more relative to what they earn.
That pushes DTIs higher, and many applicants are discovering that a strong credit score alone no longer clears the bar.
What DTI actually measures DTI is simple arithmetic.
Add up your minimum monthly payments — mortgage or rent, car loans, student loans, personal loans, and minimum credit card payments.
Divide that total by your gross monthly income before taxes.
If you earn $6,000 a month and owe $2,400 in payments, your DTI is 40%.
Most conventional loans want that number at or below 43%, though some lenders allow up to 45% or 50% with compensating factors like large cash reserves.
FHA loans often permit ratios near 50% with documentation.
Why it matters more right now Two forces are squeezing the ratio from both directions.
Credit card APRs have been running above 20% on average, so minimum payments on the same balance are bigger than they were three years ago.
Meanwhile, wage growth has cooled, meaning the denominator — your income — isn't climbing as fast as the debt side.
A $1,800 rent payment eats a chunk of income that lenders count as debt, so saving for a down payment while renting can leave you with a ratio that looks worse than your finances actually are.
The traps that blow up applications Lenders pull your credit report at pre-approval and again before closing.
Opening a store card for a furniture discount, financing a car, or co-signing a sibling's loan in that window can push you over the limit and kill the deal.
Lenders typically count 1% of the outstanding balance as a monthly payment when the loan is in deferment, even if you're paying $0.
That phantom payment has derailed plenty of otherwise solid buyers.
How to move the needle Paying down revolving debt is the fastest lever, because credit cards carry the highest minimum payments relative to balance.
Knocking $5,000 off card balances can free up $100 to $150 a month in required payments — real relief for your ratio.
If you received a raise or started a side gig, ask whether the lender can count it.
Overtime, bonuses, and self-employment income follow specific rules, but they can be included with the right paperwork.
Shopping with the right loan type matters.
Some lenders specialize in higher-DTI borrowers, and certain government-backed programs are more flexible than conventional guidelines.
A mortgage broker who works with multiple lenders may find options a single bank won't.
Run your own numbers before anyone else does.
Add your minimum payments, divide by gross monthly income, and see where you stand.
If you're above 43%, start paying down cards now rather than after you find a house you love.
The takeaway DTI has become the quiet gatekeeper of the housing market, and it punishes the wrong things — high rent, old student loans, and a credit card balance from two winters ago.
Knowing your number early gives you time to fix it instead of scrambling at closing.
Final Thoughts
Do the math before a lender does it for you.