Mortgage rates have cooled from their recent peaks, and plenty of buyers assume that's the green light they've been waiting for.
Then the pre-approval comes back denied, or approved for thousands less than expected.
The culprit often isn't credit or savings.
It's a number most shoppers have never checked: their debt-to-income ratio.
Lenders add up your minimum monthly debt payments, divide that by your gross monthly income, and get a percentage.
That single figure drives how much house you can afford, and in many cases, whether you get a loan at all.
Mortgage rates hovering in the 6% range mean each dollar borrowed costs more, so monthly payments eat a bigger slice of income.
When payments climb, DTI climbs with them, even if your salary hasn't changed.
The old rule of thumb was the 28/36 guideline.
Housing costs under 28% of gross income, all debt under 36%.
That standard is ancient history for many buyers.
Most conventional loans today allow total DTI up to 43%, and some programs stretch to 45% or even 50% with compensating factors like a large down payment or healthy cash reserves.
FHA loans have long been more flexible, and that flexibility is a big reason they stay popular with first-time buyers.
A 50% DTI means half your gross pay is spoken for before taxes, insurance, and groceries even enter the picture.
Student loans, car payments, minimum credit card payments, personal loans, and child support all count.
What usually doesn't count: utilities, phone bills, streaming subscriptions, and daycare.
Those still drain your bank account, but lenders typically ignore them.
Minimum payments are small, so a $12,000 balance might only add $250 to your monthly debt load.
But if you're carrying balances across five cards, those minimums stack up fast.
Paying down revolving debt before applying can move your DTI more than saving another few thousand dollars for a down payment.
Add up every minimum monthly payment you're obligated to make.
If it's above 43%, expect pushback from conventional lenders.
If it's above 50%, you'll need a strong story, a bigger down payment, or a co-borrower.
Pay off small balances, avoid financing a car in the months before you house hunt, and don't open new credit lines mid-process.
A single new auto loan can blow up a carefully planned approval.
One more thing: lenders calculate DTI using the new mortgage payment, not your current rent.
So a cheap apartment today doesn't protect you if the house you want pushes you past the limit.
Our take: DTI is the most ignored number in homebuying, and it's also the most fixable.
Check yours months before you shop, not the week you fall in love with a listing.
Final Thoughts
A little boring math now beats a rejected offer later.