Mortgage preapproval: what lenders check, how long it lasts

What is a preapproval letter?

A preapproval letter shows sellers you are a serious buyer. The Consumer Financial Protection Bureau (CFPB) says lenders “preapprove you by looking at your income, assets, debts, and credit record.” The letter rests on assumptions, so it does not commit the lender to make the loan. It does not commit you to that lender either.

Lenders use the words inconsistently. Some call an unverified estimate a “prequalification” and keep “preapproval” for a review of documents you have supplied. Others use one word only. Ask the lender what it verified and which assumptions it made, and whether anything could lead to a denial or higher costs later. Compare the verification, not the label.

What do lenders check?

Four things matter: income, assets, debts and credit.

• Income and assets. The lender looks for stable income and funds for the down payment, closing costs and reserves. The CFPB page does not give a document list and says every lender is different. Ask early what the lender requires, because some items take time to obtain.
• Debts and the debt-to-income ratio. The ratio compares your monthly debt payments, including the new housing payment, to your monthly income. See debt-to-income ratio.
• Credit. Lenders typically check your credit before issuing a letter. The CFPB says a lender that finds you do not qualify must send you an adverse action notice. If a credit score was used, the notice includes that score and how to get a free credit report.

What debt-to-income limits do lenders use?

Each loan program sets its own limits. As one published benchmark, Fannie Mae’s Selling Guide (B3-6-02, April 2, 2025) says that for manually underwritten loans the maximum total DTI ratio is 36% of stable monthly income. It can reach 45% if the borrower meets the credit score and reserve requirements in its Eligibility Matrix. For loans run through Fannie Mae’s automated Desktop Underwriter, the maximum is 50%.

The figures are the most the total of your monthly debts, including the new mortgage payment, taxes and insurance, could reach at each ratio. Government-backed programs have their own rules; see FHA loans, VA loans and USDA loans.

Worked example: from DTI to a loan amount. Take a gross income of $6,000 a month and $500 of existing monthly debt payments (car, student loan, cards). Room left for the full housing payment = income × ratio − $500:

The 7.24% rate is Freddie Mac’s average 30-year fixed rate for the week of October 29, 2026, used only for illustration; the $400 for taxes and insurance is an assumption. Loan amount = P&I × (1 − (1 + r)^−360) ÷ r, with r = 7.24% ÷ 12. Your lender uses your actual rate, taxes, insurance and any mortgage insurance. See how much house can I afford.

Does a credit score minimum apply?

It depends on the program and underwriting method. Fannie Mae’s Selling Guide (April 22, 2026) requires a minimum credit score of 620 for manually underwritten fixed-rate loans and 640 for adjustable-rate loans. For loans run through Desktop Underwriter, it says no minimum score is required, because the system weighs the full credit file. Individual lenders can set stricter rules. For FHA loans, HUD announced on October 8, 2026 that VantageScore 4.0 and FICO Score 10T will be accepted alongside classic FICO for case numbers assigned on or after January 1, 2027. See credit score and mortgage rates.

Will shopping for a preapproval hurt my credit?

An inquiry “typically has a small negative effect on your credit scores,” according to the CFPB. But within a 45-day window, multiple credit checks from mortgage lenders are recorded as a single inquiry, as long as the last check falls within 45 days of the first. Shopping across several lenders in that window therefore costs about the same as asking one. A mortgage inquiry does not group with an auto loan inquiry.

How is a preapproval different from a Loan Estimate?

A Loan Estimate is a standardized federal form. The lender must give it to you within three business days of receiving your application. Under Regulation Z, an application for these purposes consists of six items: your name, your income, your Social Security number (to obtain a credit report), the property address, an estimate of the property’s value, and the loan amount sought. Because the property address is part of the definition, a letter issued before you have chosen a home generally comes first. The CFPB advises waiting to choose a lender until you have made an offer and received official Loan Estimates from each lender you are considering. Costs are covered in closing costs explained.

What if I am declined?

Ask why and ask to see the credit score the lender used. Correct any errors on your credit report. The CFPB suggests contacting a HUD-approved housing counseling agency, reachable at 1-800-569-4287, for help improving your credit. The next step after approval is shopping for a home; see the steps to buy a home, and plan your down payment.

Where states differ

The federal rules above apply everywhere. States differ in what happens after the letter: the purchase contract, how earnest money is held, whether an attorney handles the closing, and which state programs may add their own income or credit conditions. For state closing practices, see closing costs in Texas and closing costs in California. For state down payment help, see Texas and California first-time buyer programs.