Which FICO (Fair Isaac) Score Do Mortgage Lenders Use?

The only reliable way to know the exact FICO model a lender will use is to ask the lender directly.

1. Contact your loan officer or mortgage broker. Tell them you need to know which FICO version (e.g., 5, 5.1, 6, 8, 9) will be applied to your credit‑pull. Most lenders will state the model in writing or during the pre‑approval conversation.
2. Review any credit‑pull disclosure or pre‑approval letter. Some lenders include a line such as 'We will run a FICO 9 score.' If the document is silent, treat it as a prompt to ask again.
3. Identify the automated underwriting system (AUS) the lender uses. If the lender runs Fannie Mae's Desktop Underwriter or Freddie Mac's Loan Product Advisor, know that both accept multiple FICO versions - typically 5, 5.1, 6, 8, and 9. Knowing the AUS narrows the likely models but does not guarantee a single version.
4. Ask the underwriter during the underwriting phase. When the file moves from the loan officer to the underwriter, request confirmation of the exact FICO version that will be used for the final decision.
5. Document the answer. Keep a copy of the lender's response (email or written note) for future reference, especially if you need to compare offers or verify the score used at closing.

These steps ensure you have a definitive answer, since neither the Loan Estimate nor the tri‑merge report indicates the FICO version.

• Lenders typically take the middle FICO score from the tri‑merge report as the number you'll see on your loan estimate.
• Get your tri‑merge report from any of the three bureaus or from a service like MyFICO credit report.
• Locate the three FICO scores, order them low‑high‑low, and use the one in the middle as the 'middle score.'
• If the three scores differ by more than 20 points, lenders often request a fresh pull; otherwise the middle score serves as the qualifying figure for automated underwriting.

Automated underwriting systems pull the tri-merge report, extract the three bureau FICO scores, and typically apply the middle score - the median of the three - to the loan analysis. Fannie Mae's Desktop Underwriter, for example, always uses that median; it does not swap to the highest or lowest score based on perceived risk.

Often a specific loan program overrides the default. FHA, VA, and USDA guidelines may instruct the engine to use the lowest bureau score, but the core underwriting model still starts with the middle score before any program‑specific rule is applied. This explains why the 'find the tri‑merge middle score lenders use for you' step matters before you move on to 'see how your loan type affects the FICO version used.'

The loan program you choose decides the FICO version your lender will pull from the tri‑merge report; conventional, VA and USDA loans typically use the FICO 5 model, while FHA and many non‑QM products often rely on FICO 4. Below is the typical match‑up:

• Conventional (conforming, jumbo) - FICO 5 (sometimes FICO 8, but FICO 5 is the default)
• FHA - FICO 4 (some lenders have moved to FICO 5)
• VA - FICO 5 (occasionally FICO 8)
• USDA Rural Development - FICO 5
• Non‑QM / alternative loans - FICO 4 or FICO 8, depending on the lender's automated underwriting
• Cash‑out refinance - uses the same version as the original loan plus the lender's chosen version, often FICO 5

Mortgage lenders read the exact FICO versions that appear in the tri‑merge report - typically FICO 2 from Experian, FICO 4 from TransUnion, and FICO 5 from Equifax - so you can't request a uniform model or convert scores after the pull.

• Identify each bureau's version: Experian (Score 2), TransUnion (Score 4), Equifax (Score 5).
• Pull your own consumer reports now and note the three scores; they will match the lender's tri‑merge.
• If one score is significantly lower, address the underlying reason (pay down balances, dispute inaccuracies) before the lender's pull.
• Remember the lender will use the three scores exactly as reported; no conversion chart or re‑issuance is possible.
• The middle score of the three reported numbers determines eligibility and rate, so focus on bringing the lowest score up to improve that middle value.

Having the three scores under control lets the middle score work in your favor, which the next section explains when lenders default to the lowest score.

Lenders pull your lowest FICO score when a loan program or underwriting rule requires every bureau to meet a minimum, so the smallest number becomes the qualifying figure. For example, FHA, VA and USDA guidelines treat the lowest of the three bureau scores in the tri‑merge report as the official score; Desktop Underwriter will also flag risk and automatically select the lowest if it falls below the model's cut‑off.

In most conventional scenarios lenders rely on the middle score from the tri‑merge report because it smooths out outlier values and generally satisfies the 'average' requirement set by Fannie Mae and Freddie Mac. They will only switch to the lowest score if that number drops beneath a hard eligibility threshold - typically 620 for conventional loans and 580 for FHA - otherwise the middle score determines your qualification. Fannie Mae's Desktop Underwriter guidelines

Lenders let you apply co‑borrower rules to replace the lowest middle score on the tri‑merge report with the higher score of a qualifying partner, thereby raising the score that determines eligibility.

If you and your spouse each have a middle score of 720 and 660, the lender normally uses the lower 660. Because the 660 belongs to a non‑primary spouse with only a small credit‑card balance, the lender can drop that borrower from the credit‑score calculation and base the qualification on the 720 instead.

Similarly, a primary borrower with a 750 middle score and a co‑borrower with 680 can keep the 750 as the qualifying score when the co‑borrower's debt‑to‑income ratio is minimal and the loan program permits a 'non‑primary exclusion.' This rule often appears in the '5 quick score moves lenders actually accept before closing' section later in the article.

Here are five quick score moves lenders actually accept before closing:

• Pay down high‑balance credit cards to push utilization below 30% (often below 10%); the lower utilization raises the middle score on the tri‑merge report.
• Request a goodwill or correction for a single recent late payment; once the bureau updates the entry, lenders typically see the improved FICO score in the final pull.
• Dispute any factual errors (e.g., wrong account status or duplicated entry); corrected items instantly boost the middle score used by underwriting.
• Ask the issuer for a credit‑limit increase that does not trigger a hard inquiry; a higher limit reduces utilization and often lifts the middle score.
• Add a co‑borrower with a clean, higher FICO score; the combined tri‑merge middle score is recalculated and often meets lender thresholds.

Medical collections lower your mortgage FICO because they appear on the tri‑merge report and become part of the middle score, but newer versions (FICO 9, 10, 10T) often ignore medical debt that is paid or older than seven years (FICO Score 9 medical collection rules). Older models (FICO 04, 02, 05) still count every medical account, regardless of status.

Paid collections usually drop out of the calculation in the newer models, yet the account remains visible on the tri‑merge, so lenders may still apply the lower middle score from an older version. An unpaid medical collection from the past 12 months can shave 10‑30 points off the middle score; once it's marked paid, the impact fades after about a year in the newer scores, but you may need to wait for the tri‑merge to reflect the change before re‑applying.

Locking your credit prevents new inquiries, but lenders need a temporary thaw to pull the tri‑merge report and calculate the middle score that will be used for underwriting.

1. Verify your current freeze status with Experian, Equifax and TransUnion.
2. If you have a lock, schedule a 30‑ to 45‑day thaw that aligns with the lender's expected pull date.
3. Tell your loan officer the exact thaw window so the automated underwriting system can access the tri‑merge report without delay.
4. Keep the lock in place for the rest of the mortgage process; this freezes the FICO score used for the middle score and protects against unexpected drops.
5. Monitor the credit file during the thaw period for any unauthorized pulls and re‑freeze immediately after the lender's final check.

For more on how credit freezes work, see what is a credit freeze.