A $415,000 listing keeps showing up in your saved searches. You have a steady job, a decent chunk in savings, and no real idea whether a lender would hand you a number on the spot or quietly change the subject. That gap between I think I can afford this and here is what a lender will actually lend me is what prequalification fills.
It takes about as long as a coffee break, costs nothing at most lenders, and usually leaves no mark on your credit report. Here is what happens during a mortgage prequalification, what the number really means, and where buyers get tripped up.
What prequalification actually is
Prequalification is a rough math exercise. You report your income, your monthly debts, how much cash you have for a down payment, and roughly where your credit sits. The lender pushes those figures through debt-to-income guidelines and hands back a loan amount and a price range, usually as a letter you can forward to your real estate agent.
Most of what you say is unverified at this stage. Nobody has pulled tax returns or called your employer. That is the whole point. It is fast because it is shallow.
Prequalification versus preapproval
Preapproval is the version with receipts. You upload pay stubs, W-2s, two months of bank statements, sometimes full tax returns. The lender pulls your credit, an underwriter reviews the file, and you get a conditional commitment. That takes days rather than minutes, and sellers take it far more seriously.
On a house that collects three offers in a weekend, a preapproval letter is often what gets your offer read at all. Prequalification is the step that tells you whether preapproval is even worth starting.
The numbers a lender runs
Everything funnels into a single ratio: how much of your gross monthly income goes toward debt payments, including the new mortgage. Conventional loans typically top out around 43% to 45% debt-to-income, though automated underwriting can stretch higher when other factors are strong. FHA often allows 50%. VA is more flexible still.
Here is the arithmetic on a fairly typical file. Gross income of $9,000 a month. A $520 truck payment, $230 in student loans (lenders count 1% of the balance when the loan is deferred), and roughly $150 in minimum credit card payments. That is $900 in existing debts.
- 43% of $9,000 leaves $3,870 for total monthly debt payments
- Subtract the $900 in existing debts and you have $2,970 for principal, interest, taxes, and insurance
- Taxes, insurance, and any HOA dues on the kind of house you are eyeing run about $1,150 a month
- That leaves roughly $1,820 for principal and interest
At current rates, $1,820 a month supports a loan near $285,000. Add 10% down and you are shopping just over $315,000, not the $415,000 you were scrolling past at midnight. That is the moment prequalification earns its keep.
Does asking hurt your credit?
Usually not. The large majority of lenders use a soft inquiry for prequalification, which leaves no trace. Ask the loan officer directly before you begin, because a small number still run a hard pull, and a hard pull shaves a few points off your score for about a year.
If you go on to get preapproved with three lenders to compare rates, FICO treats mortgage inquiries inside a 45-day window as one shopping event. Rate shopping in a single focused burst does far less damage than three separate pulls spread across three months.
What to have in front of you
Gather this and the conversation takes fifteen minutes:
- Gross monthly income, plus a sense of how much of it is bonus or overtime
- Minimum payments on every debt: cards, car loans, student loans, personal loans, child support
- Total cash available, split between down payment and reserves
- Where the down payment is coming from, especially if a relative is gifting it
- Your best guess at your credit score, which most banks will show you for free
If you would rather see the sequence laid out first, a practical walkthrough of the prequalification process covers the order the questions come in and what each answer changes.
When credit is the weak link
You do not need an 800 score. Conventional loans generally start at 620. FHA goes down to 580 with 3.5% down, or 500 with 10% down. VA and USDA set their own floors and tend to be more forgiving of old dings than their published guidelines suggest.
Below those marks, the answer is not no. It is a different lender. Non-QM and portfolio lenders underwrite the whole file rather than the score, which means twelve months of on-time payments and a documented explanation for an old collection can matter more than the three-digit number. Finding lenders who genuinely work with bruised credit is often a bigger hurdle than qualifying itself.
Where prequalified numbers go sideways
What a lender quotes is a ceiling, not a budget. Several things routinely push the real payment past it.
Property taxes swing hard by state
Texas rates run near 1.6% to 1.9% of assessed value. Colorado sits closer to 0.5%. On a $400,000 house that spread is several hundred dollars a month in escrow, and it moves your affordability more than a quarter-point change in interest rates.
Daycare and commuting never show up in the file
Debt-to-income counts obligations, not lifestyle. $1,600 a month in childcare does not appear anywhere in the calculation, and neither does the extra $300 in fuel you will spend after moving twenty miles farther out for a bigger yard.
New construction and the year-two escrow jump
Taxes on a newly built home are frequently assessed the following year, based on the finished value rather than the raw land. Payments climb. Budget for a 10% to 15% escrow increase in year two and it will not blindside you.
Closing costs live outside the purchase price entirely, typically 2% to 5% of the loan amount. On a $300,000 loan that is $6,000 to $15,000 in cash on top of your down payment.
Getting real value out of the letter
Prequalification letters usually stay valid for 60 to 90 days. Before yours expires, do three things.
Treat the quoted figure as a ceiling and set your actual search limit 10% to 15% beneath it. The payment you can technically qualify for and the payment you will happily make for thirty years are rarely the same number.
Then sit with the monthly payment instead of the purchase price. A $340,000 house in a high-tax county can cost more each month than a $365,000 house in a low-tax one, and the listing price will never tell you that.
Finally, avoid anything that scrambles the file between prequalification and closing. No new auto loan, no financed furniture, no leap into a commission-only role, no large unexplained deposits landing in your checking account. Lenders re-verify everything at the finish line, and surprises there cost real money.
Call two more lenders and stack the numbers side by side. Prequalification is free, and inside that rate-shopping window it is painless. Half an hour spent comparing three offers is frequently worth five figures across the life of the loan.