A mortgage commitment letter is your lender’s formal, underwritten promise to fund your home loan on specific terms. It comes after a full review of your finances and, usually, the property, and it goes well beyond pre-approval. Pre-approval estimates what you might borrow. A commitment letter says the lender has verified your file and intends to close, subject to whatever conditions the letter spells out. For sellers evaluating an offer, it is the document that signals the buyer’s financing is real.
Conditional vs. Final Commitment
Lenders issue two versions of this letter, and the difference matters more than most borrowers realize.
A conditional commitment letter means the lender has reviewed your application and is generally willing to lend, but specific items still need to be resolved. Those outstanding items might include a satisfactory property appraisal, proof of homeowners insurance, verification that your down payment funds are in the right account, or additional documentation the underwriter flagged during review.
A final commitment letter means every condition has been satisfied. The lender has vetted your financial situation, confirmed the property’s value and condition, and is ready to fund the loan for a specific amount, at a specific rate, on a specific property. This is the version that truly commits the lender. If you are a seller weighing an offer, a conditional commitment still carries real risk that the deal falls through; a final commitment means the lender is essentially writing the check.
What the Letter Contains
The letter spells out the exact terms of the loan the lender is offering. You will see:
- The approved loan amount.
- The interest rate, and whether it is locked.
- The loan program, such as a 30-year fixed-rate mortgage or a 5/1 adjustable-rate mortgage.
- The required down payment.
- The property address.
- Any remaining conditions that must be satisfied before funding.
- An expiration date.
Even a final commitment often lists a handful of closing conditions. These are typically administrative: proof of homeowners insurance meeting the lender’s minimum coverage, a clear title search, and a verbal verification of your employment shortly before closing. Lenders generally complete that employment check within 10 business days of closing to confirm you have not changed jobs since underwriting.
Rate Locks and Expiration Dates
Every commitment letter carries an expiration date, typically 30 to 60 days from issuance. That deadline is usually driven by your interest rate lock, a contractual agreement that holds your rate for a set period. Rate locks commonly run 30, 45, or 60 days.1Consumer Financial Protection Bureau. What’s a Lock-In or a Rate Lock on a Mortgage? If closing gets pushed past that window, things get expensive.
Extending a rate lock typically costs 0.125 to 0.375 percent of the loan amount for each 15-day extension. On a $400,000 loan, that is $500 to $1,500 per extension. Some lenders offer a “float-down” option that lets you capture a lower rate if the market improves during your lock period, though this usually comes with its own fee. If you let the lock expire entirely, you will re-lock at whatever rate the market offers that day, which could be higher.
Your supporting documents also have a shelf life. Fannie Mae requires credit documents to be no more than four months old on the date you sign the note.2Fannie Mae. Allowable Age of Credit Documents and Federal Income Tax Returns If closing drags past that window, the lender will need a fresh credit report and possibly updated pay stubs and bank statements. Each refresh introduces the risk that something in your financial picture has changed.
If your commitment is about to expire and the delay is not your fault, talk to your lender right away. Most will extend, but you may need to resubmit recent financial documents. If the seller caused the delay, your purchase contract sometimes shifts extension fees to the seller’s side of the ledger.
How a Commitment Can Be Revoked
A commitment letter is not a guarantee. The lender’s promise holds only as long as your financial profile stays the same as it was when they underwrote your file. Deals fall apart when it doesn’t.
The most common revocation triggers are changes the borrower makes between commitment and closing. Taking on new debt is the fastest way to kill a deal. Financing a car, opening a credit card, or co-signing someone else’s loan changes your debt-to-income ratio and can push you outside the loan program’s limits. Lenders catch this because they run a final credit check shortly before closing specifically to look for new accounts, inquiries, or undisclosed liabilities.3Equifax. Undisclosed Debt Monitoring Equifax found that roughly 10 percent of mortgage applicants opened other loans during the origination process.
Job loss or a job change is the other big risk. If the verbal employment verification shows you are no longer at the same company that appeared on your application, the lender will likely pull the commitment until it can re-underwrite with your new income. Even a lateral move to a comparable salary can delay things, because the lender wants to see stability.
Other triggers include letting a condition go unmet past its deadline, a property issue discovered during the final walkthrough, and a significant drop in the appraised value. The commitment can also be revoked if the lender discovers inaccurate information on your original application, regardless of whether the error was intentional.
What to Avoid Between Commitment and Closing
The stretch between your commitment letter and closing day is not the time to make financial moves. Treat it as a financial freeze:
- Do not open new credit accounts or apply for any loans, including store financing offers. Each application generates a hard inquiry and a potential new obligation.
- Do not make large purchases that deplete your cash reserves. Furniture and cars can wait.
- Do not make large, unexplained deposits into your bank accounts. If a relative is gifting you closing-cost money, document it with a gift letter. Random deposits require explanation and slow things down.
- Do not close existing credit accounts. Shutting down a credit card changes your utilization ratio and can lower your score.
- Do not change jobs unless you absolutely must. If a change is unavoidable, tell your loan officer immediately rather than hoping nobody notices.
- Do not switch banks. Moving accounts forces the lender to re-verify your assets at the new institution.
The lender’s final checks are designed to catch exactly these kinds of changes. Staying financially boring until the deal closes is the single best thing you can do to protect your commitment.
What Produces the Letter
Before the letter is issued, an underwriter verifies every number you provided and confirms you meet the lender’s and the loan program’s requirements. They cross-check your stated income against IRS transcripts, confirm your employment is current, review your credit history, and ensure the appraisal supports the purchase price. For qualified mortgages, the loan must also meet price-based thresholds set by the Consumer Financial Protection Bureau.4Consumer Financial Protection Bureau. General QM Loan Definition
If the underwriter finds problems, they issue a list of conditions you need to clear. Common conditions include explaining a gap in employment, documenting a large deposit, or providing an updated pay stub. Responding quickly keeps the process moving. If your file cannot be approved, you are entitled to know why: under the Equal Credit Opportunity Act, the lender must notify you of its decision within 30 days of receiving your completed application, and a denial must include the specific reasons your application was rejected.5Office of the Law Revision Counsel. 15 USC 1691 – Equal Credit Opportunity Act
One number the underwriter watches closely is your debt-to-income ratio, which divides your total monthly debt payments by your gross monthly income. The threshold varies by loan program. Conventional loans backed by Fannie Mae can allow ratios up to 45 or even 50 percent for borrowers with strong credit and cash reserves. FHA loans generally cap at 43 percent. VA and USDA loans use 41 percent as a benchmark. Large unexplained deposits in your bank statements draw extra scrutiny because the underwriter needs to confirm those funds are not a hidden loan.
From Commitment to Closing
Once you hold a final commitment letter and all conditions are cleared, the lender prepares the Closing Disclosure, a standardized document laying out every cost, credit, and term of your loan in final form. Federal law requires the lender to deliver this disclosure at least three business days before you sign the closing documents.6Consumer Financial Protection Bureau. TILA-RESPA Integrated Disclosure FAQs That window exists so you can review the numbers and catch discrepancies before you sit down at the closing table.
Compare the Closing Disclosure line by line against the Loan Estimate you received earlier. Your interest rate, loan amount, and monthly payment should match what the commitment letter promised. Certain closing costs can increase between the estimate and the disclosure; others are legally capped. If something looks wrong, raise it with your loan officer before the three-day window expires. Certain changes to the APR or loan product will reset that clock and delay your closing.
At the closing itself, you sign the mortgage note and deed of trust, the lender wires the funds, and the title company records the transaction. The commitment letter’s job is done once the wire hits.