For Mortgage Loan Processors ·
What you'll accomplish
By the end of this guide, you'll use Claude as a "second set of eyes" to verify your income calculations for complex borrowers — self-employed, rental income, commission-heavy — before you submit to underwriting. Catching your own errors before UW does saves re-submission time and builds your credibility.
What you'll need
Go to claude.ai and start a new conversation. You don't need a Project for this — any free chat works.
Important: Do NOT upload actual tax return PDFs or documents containing full SSNs, account numbers, or other sensitive PII to any AI tool. Type the key figures manually instead.
Type a structured prompt that gives Claude the income figures, the loan program, and the calculation method you used.
Use this template:
I'm a mortgage processor verifying income for a [LOAN TYPE] loan. Please help me check my calculation.
Borrower employment type: [W-2 / Self-employed / 1099 / Commission / Rental income]
Income data I'm working with:
- [Year]: [Income figures, e.g., "2023 W-2 income: $72,000 / 2022 W-2 income: $68,500"]
- [Any additional relevant figures, e.g., "2023 YTD paystub gross: $41,200 through May 31"]
My calculated qualifying income: $[YOUR FIGURE] per month
Guideline I'm following: [e.g., "FNMA — 2-year average of base salary from W-2s"]
Please: (1) confirm or correct my calculation, (2) flag anything that might trigger a UW question, (3) note if I'm missing any standard documentation for this income type.
Claude will walk through the calculation and either confirm your figure or flag a discrepancy. It will also note:
If Claude's figure matches yours: proceed with confidence. If it differs: review the specific step where the discrepancy occurs. Claude will show its work — compare it to your own.
What you should see: A step-by-step calculation walkthrough with a qualifying income figure and any flagged items. Troubleshooting: If Claude gives you a very different number, ask it to "walk through each step of the calculation and cite the specific FNMA guideline basis." This forces it to show exactly where the difference comes from.
If the calculation checks out, ask Claude in the same conversation: "Now write a 2-paragraph income narrative memo summarizing this calculation for the underwriter file."
You've now done verification AND documentation in one session.
Self-employed (Schedule C):
Verify income for self-employed borrower, FNMA guidelines. Schedule C net profit: 2023: $[X], 2022: $[X]. Business mileage deduction: $[X] both years. Non-recurring loss in 2022: $[X]. My qualifying income: $[X]/month. Confirm calculation and flag UW concerns.
Rental income (Schedule E):
Verify rental income calculation, FNMA guidelines. Schedule E: Property at [address]. Gross rent 2023: $[X], 2022: $[X]. Mortgage interest: $[X]. Taxes: $[X]. Depreciation: $[X]. Insurance: $[X]. My net qualifying income using 75% rule: $[X]/month. Is this correct?
Retirement income:
Verify retirement income. Borrower age: [X]. Social Security award letter: $[X]/month. IRA distribution (verified 2-year history): $[X]/year. Is this fully qualifying income for a conventional loan, and what documentation is standard?