How to Calculate K-1 Income for a Mortgage: Add-Backs and Liquidity

To calculate K-1 income for a mortgage, a lender starts with the ordinary business income in Box 1 of your Schedule K-1, adds back non-cash expenses like depreciation and amortization, subtracts the non-deductible portion of meals and entertainment, adds any guaranteed payments (for partnerships), averages the result across the two most recent tax years, and then confirms the business can actually distribute that money to you. The headline figure on the K-1 is only the starting point. The number the underwriter plugs into your debt-to-income ratio is often meaningfully lower.

Start With Box 1 and the Two-Year Average

Box 1 of your Schedule K-1 reports your share of the business’s ordinary income or loss from operations.¹ That figure is the foundation for everything that follows.

The underwriter pulls Box 1 from each of your two most recent tax years, applies the adjustments described below, adds the two adjusted annual figures together, and divides by 24 to get a monthly qualifying number. Fannie Mae generally requires this two-year history as the baseline for demonstrating that the income will likely continue.² Less than two years of self-employment history isn’t automatically disqualifying under conventional guidelines. Income received for at least 12 months may be acceptable if there are positive factors to offset the shorter track record.³

Add Back Non-Cash Expenses

Tax returns include deductions for expenses that didn’t actually cost the business any cash in the current year. Fannie Mae’s Form 1084 cash flow analysis worksheet specifies exactly which items to restore:⁴

Depreciation. The business deducted this on its tax return for wear and tear on equipment, buildings, or vehicles, but no cash actually left the business. The full depreciation amount from the business return, including Form 8825 for real estate, gets added back.
Depletion. Similar concept for businesses that extract natural resources. The depletion deduction gets added back entirely.
Amortization and non-recurring casualty losses. Amortization of intangible assets like goodwill or startup costs is a paper expense, so it’s added back. One-time casualty losses are also restored since they aren’t expected to repeat.

Each of these increases your qualifying income above the Box 1 figure.

Subtract Non-Deductible Meals and Entertainment

This adjustment moves in the opposite direction and catches many borrowers off guard. Businesses can only deduct a portion of meals and entertainment expenses on their tax returns, so some of those costs show up on Schedule M-1 as non-deductible expenses. The underwriter subtracts that non-deductible portion from your qualifying income, because it represents real cash the business spent that didn’t reduce taxable income.⁴ If your business has heavy entertainment spending, this line can knock thousands off your qualifying figure.

Add Guaranteed Payments for Partnerships

If you’re a partner who receives guaranteed payments for services, those amounts appear in Box 4a of your partnership K-1. These payments function like a salary from the partnership, paid regardless of whether the business turned a profit that year. As long as you have a two-year history of receiving them, guaranteed payments can be added to your qualifying income on top of your share of ordinary business income.⁵ Guaranteed payments are a partnership concept only. S-corporation K-1s don’t have an equivalent line.

Partnership vs. S-Corporation Box Numbers

The calculation framework is the same for both entity types, but the K-1 forms use different box numbers, and pulling the wrong line gives the wrong number.

On a partnership K-1 (Form 1065), cash distributions appear in Box 19, Code A.¹ On an S-corporation K-1 (Form 1120-S), distributions appear in Box 16, Code D.⁶

S-corporation shareholders who actively work in the business typically receive W-2 wages in addition to their K-1 income. Both streams count toward qualification. The W-2 portion is straightforward. The K-1 portion still runs through the full cash flow analysis with the add-backs and deductions above.⁷ An unusually low W-2 salary paired with large K-1 distributions can create questions about whether the business is paying reasonable compensation, which the IRS scrutinizes and lenders notice.

The Business Liquidity Test

A healthy adjusted Box 1 figure doesn’t automatically translate to qualifying income. The underwriter needs to confirm one of two things: either you’ve been consistently receiving cash distributions at a level matching the income on your K-1, or the business has enough liquidity to support withdrawing those earnings without crippling the company.⁵

A documented, stable history of distributions matching your reported income is the simplest path. No further liquidity analysis is needed. When distributions fall short of reported income, which is common for businesses reinvesting profits, the lender tests the business’s financial health using one of two standard ratios:⁸

Current ratio. Current assets divided by current liabilities. Best for businesses that don’t rely heavily on inventory. A result of 1.0 or higher generally passes.
Quick ratio. Current assets minus inventory, divided by current liabilities. Used for inventory-heavy businesses, since inventory can’t always be quickly converted to cash. Again, 1.0 or above is the target.

A ratio below 1.0 means the business doesn’t have enough short-term assets to cover its short-term obligations, let alone support pulling money out for your mortgage payments. In that situation, the underwriter will typically cap your qualifying income at whatever the business has actually been distributing, not what the K-1 says you earned on paper.⁸

What Happens When the K-1 Shows a Loss

Plenty of K-1s show negative numbers, especially for passive investors in real estate partnerships or businesses in early growth stages. A K-1 loss doesn’t just zero out income from that entity. It can reduce your overall qualifying income from other sources, including W-2 wages or income from other businesses. The underwriter calculates your total cash flow across all income streams, and a K-1 loss works against you in that combined picture.

If you have multiple K-1s, some profitable and some showing losses, the losses offset the gains before the underwriter arrives at your net qualifying figure. You might earn $200,000 from one partnership and show a $50,000 loss on another. Your qualifying K-1 income isn’t $200,000; it’s the net after deducting the loss.

Declining Income Between the Two Years

When the most recent year’s adjusted income is lower than the prior year, the two-year average may not stand. Fannie Mae requires that the business’s income be stable and consistent, with positive sales and earnings trends. If the business doesn’t meet those standards, the income cannot be used to qualify you at all.⁷ A modest dip might be explainable. A significant year-over-year decline often leads the underwriter to use only the most recent, lower 12-month figure rather than the two-year average, reducing your qualifying income.

For FHA loans, the rule is more concrete: if your effective income declined by more than 20% over the analysis period, the lender must downgrade the file and underwrite it manually, which means tighter scrutiny and potentially stricter qualifying standards.⁹

The 25% Ownership Threshold and What Documents Feed the Math

The scope of the calculation depends on how much of the business you own. Fannie Mae treats anyone with a 25% or greater ownership interest as self-employed, which triggers a full cash flow analysis using the business’s own tax returns.² If you own less than 25%, the lender primarily looks at your history of actually receiving cash distributions from the business rather than running the full add-back analysis.⁵

To run the calculation, the underwriter needs your personal federal tax returns (Form 1040) for the most recent two years, including all schedules, plus the Schedule K-1 forms you received. Partnership and LLC K-1s come from Form 1065; S-corporation K-1s come from Form 1120-S.¹

At 25% or above, you’ll also need the full business tax returns for the same two-year period, including all schedules and the balance sheet. Some lenders will waive the business returns if the borrower’s share of income on the K-1 is relatively small and personal returns tell a consistent story, but expect to be asked for everything.⁵ Underwriters also commonly request a year-to-date profit and loss statement to verify current-year performance lines up with the trend from the tax returns.

Common Calculation Mistakes

The same errors show up over and over on K-1 files:

Adding back depreciation but forgetting to subtract the non-deductible meals and entertainment amount from Schedule M-1. This overstates income, sometimes by thousands.
Pulling distributions from the wrong box. Partnership distributions are Box 19; S-corp distributions are Box 16. Different form, different number.
Assuming Box 1 is the qualifying figure. It’s the starting point. The Form 1084 adjustments and the liquidity test both change it.
Ignoring K-1 losses from other entities. They reduce total qualifying income, including W-2 wages, before the underwriter arrives at a final number.
Reporting only personal returns when ownership is 25% or greater. Without the business returns, the underwriter can’t finish the calculation, and the file stalls.

Run the Form 1084 math yourself before applying. Borrowers who calculate it in advance rarely get surprised by the number the underwriter comes back with. Borrowers who don’t often find their qualifying income is 10% to 20% below what the tax return headline suggested.

1
Internal Revenue Service. Partners Instructions for Schedule K-1 Form 1065 (2025)
2
Fannie Mae. B3-3.5-01, Underwriting Factors and Documentation for a Self-Employed Borrower
3
Fannie Mae. Standards for Employment-Related Income
4
Fannie Mae. Cash Flow Analysis (Form 1084)
5
Fannie Mae. Income or Loss Reported on IRS Form 1065 or IRS Form 1120S, Schedule K-1
6
Internal Revenue Service. Shareholders Instructions for Schedule K-1 Form 1120-S (2025)
7
Fannie Mae. Analyzing Returns for an S Corporation
8
Fannie Mae. Analyzing Partnership Returns for a Partnership or LLC
9
U.S. Department of Housing and Urban Development. FHA Single Family Housing Policy Handbook