No. Mortgage preapproval is a lender's preliminary assessment, not a guarantee that the loan will be approved and funded. The letter is useful, but its assumptions and conditions matter as much as its headline amount.

The Consumer Financial Protection Bureau's preapproval guide explains that lenders differ in how much information they verify at this stage. The terms preapproval and prequalification are not used identically by every lender. Ask what has actually been checked rather than relying on the label.

Consider a hypothetical buyer with a letter showing a $350,000 borrowing limit. That number does not mean every $350,000 transaction is affordable or eligible. The buyer still needs a realistic budget, a suitable property and an application that satisfies the lender's remaining requirements. A change in the information behind the letter can change the result.

Useful questions for the lender include:

• Which income, asset and credit information have you verified?
• What conditions remain before final approval?
• When does this letter expire?
• What changes should I tell you about immediately?
• Is an interest rate locked, or is this only an estimate?

Keep copies of the letter and requested documents together. If a purchase contract includes a financing deadline, track that separately; a preapproval letter should not be treated as an extension of the contract.

Our mortgage qualification study guide explains the borrowing concepts. For your own purchase, compare actual loan terms and ask the lender to identify unresolved conditions in plain language. Preapproval is a useful planning step, not the finish line.