- Qualifying income comes from tax returns after add-backs, not from bank deposits or invoices. Every deduction that lowered your taxes lowered this number too.
- Stable or rising: the two years are averaged. Falling: the most recent year is used, and if the current year is still falling the income may not count at all.
- That asymmetry means a rising business doesn’t get full credit for where it is now, and a dipping one gets no credit for where it was.
- Many lenders use the lower year regardless of trend. That’s an overlay, not the guideline, and it’s worth asking about before you apply.
Three numbers, and which one is yours
A W-2 borrower has one qualifying income: what the pay stub says. A self-employed borrower has at least three candidates, and the file will be judged on whichever one the underwriter’s method produces. The calculator above shows all three so there are no surprises.
The 24-month average is the Selling Guide’s method when income is stable or increasing. The most recent year is the method when income is declining. The lower of the two years is not a guideline method at all — it’s a common lender overlay that treats every self-employed file conservatively regardless of trend. When the trend is falling, the second and third are the same number. When it’s rising, they differ, and the difference is income you earned but can’t use.
Stable or rising: (Year 1 + Year 2) ÷ 24 · Declining: Year 2 ÷ 12
The default case, read the way an underwriter reads it
Prior year $118,000 net plus $6,000 in add-backs; most recent year $102,000 plus $6,500. Year-to-date, $52,000 over seven months. Other debts $650 a month.
| Method | Monthly income | Max housing pmt at 45% DTI |
|---|---|---|
| 24-month average | $9,688 | $3,710 |
| Most recent year (declining — applies) | $9,042 | $3,419 |
| YTD run-rate | $7,429 | $2,693 |
Income fell 12.5% between the two return years and the current year is running 17.8% below the most recent one.
Three readings of one business. The optimistic one supports a $3,710 housing payment; the guideline one, $3,419; and the current-year run-rate, if the underwriter conditions on it, $2,693. That last figure is the one to plan around, because a 17.8% year-to-date drop against a return year that was already down is the pattern that triggers the stability question — and under the guideline, income that is still declining may not be usable at all.
The borrower in this example is not in trouble. They’re a solid earner with a soft year. But if they walked in expecting to qualify on $10,000 a month because that’s roughly what the business produced two years ago, the gap between expectation and file would be a third of their housing budget. Better to see that here.
What add-backs are, and what they aren’t
Form 1084 — Fannie Mae’s cash-flow analysis worksheet — starts with net profit and restores deductions that reduced taxable income without reducing cash: depreciation, depletion, amortization, business use of home, and documented one-time expenses. Those are the add-backs. A vehicle depreciation deduction of $6,000 becomes $6,000 of qualifying income again.
What doesn’t come back: ordinary business expenses, owner draws that exceed profit, and anything the underwriter can’t tie to a specific line on the return. The instinct to enter a generous add-back figure is understandable and self-defeating — if the number can’t survive the worksheet, it can’t survive underwriting. Enter what a lender would actually allow.
Non-cash deductions
Depreciation, depletion, amortization, casualty losses. The business kept the cash; the return just didn’t show it.
Documented one-time items
An unusual, non-recurring expense with a paper trail. The underwriter has to agree it won’t recur.
Ordinary expenses
Rent, payroll, supplies, marketing. Those are the cost of producing the income; they stay deducted.
Business debt you’re personally on
If you personally guaranteed a business loan, its payment goes into your DTI unless the business is shown paying it.
The asymmetry, and why it’s there
Rising income is averaged. Falling income is scored on the lower year. Read those two rules together and the shape is clear: the guideline is built to lag on the way up and lead on the way down. A business that grew from $90,000 to $130,000 qualifies on $110,000. A business that fell from $130,000 to $90,000 qualifies on $90,000 — and might not qualify at all if the current year keeps falling.
The reasoning isn’t hostile. Self-employment income is more variable than a salary, and a lender is trying to estimate what will still be there in year three of a thirty-year loan. Averaging a rise means the higher year has to persist before it counts fully; scoring a fall on the lower year means the higher year is no longer treated as reliable. The rules are consistent with each other. They are just not symmetric with the borrower’s experience of their own business.
In practice, the applied treatment is often stricter than the written one. Lenders that use the lower year regardless of trend, that require YTD documentation on any decline, or that won’t accept a year-over-year drop above a threshold of their own choosing are applying overlays. The calculator’s “lower year” column is there so you can see what that looks like on your numbers before you find out from a decline.
What this calculator can’t know
It applies the two-year framework to whatever you enter. It doesn’t know your business structure (Schedule C, S-corp distributions versus W-2 wages from your own company, partnership K-1s all flow differently), whether the business can support the distributions you took, or what your specific lender’s desk will allow as an add-back. It also doesn’t know about the alternatives — bank-statement and other non-QM programs exist for exactly the borrower whose returns understate their cash flow, at a rate premium that is itself a total-cost question. Use the tool to see which of the three numbers is yours, then bring the returns to someone who can run the actual worksheet.