Form 1040 Schedule C Line 31 Explained: Net Profit, Schedule SE, and Lender Math

Short answer: On IRS Form 1040 Schedule C, Line 31 reports your business net profit or (loss) for the tax year — calculated as gross income on Line 7 minus total expenses on Line 28 and business use of home expenses on Line 30. That single Line 31 number is the most important figure on a sole proprietor’s return: it flows to Schedule 1 Line 3 for income tax, to Schedule SE Line 2 for the 15.3% self-employment tax (after the 92.35% multiplier), and to Form 8995 for the 20% QBI deduction.

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Most 1099 contractors and solo business owners spend all year looking at their gross deposits — the top-line revenue on Line 1. Neither the IRS nor a mortgage underwriter taxes or qualifies you on Line 1. Everything in the federal tax code and in self-employed lending starts at Line 31 of IRS Form 1040 Schedule C. How the earlier lines feed into it is covered in Schedule C line items explained and Schedule C explained.

How is Form 1040 Schedule C Line 31 calculated step by step?

Line 31 sits at the very bottom of Part II of Schedule C (Expenses), right before Part III (Cost of Goods Sold). It is the end result of a three-stage subtraction from your gross receipts:

1. Part I — Gross Income (Line 7): Take your gross receipts or sales on Line 1 (including all 1099-NEC, 1099-K, and non-1099 cash/check client payments), subtract returns and allowances (Line 2) and Cost of Goods Sold from Part III (Line 4), and add any other business income (Line 6) to arrive at Line 7 (Gross income).
2. Part II — Tentative Profit or Loss (Line 29): Sum every ordinary and necessary operating deduction across Lines 8 through 27a (advertising, car and truck mileage or actual expenses on Line 9, contract labor on Line 11, depreciation on Line 13, insurance on Line 15, legal and professional services on Line 17, supplies on Line 22, deductible meals on Line 24b, utilities on Line 25, and other expenses on Line 27a) onto Line 28 (Total expenses). Subtract Line 28 from Line 7 to get Line 29 (Tentative profit or loss).
3. Line 30 — Expenses for Business Use of Your Home: Subtract either your simplified home office deduction ($5 per square foot up to 300 square feet, max $1,500) or your actual home office deduction from Form 8829.
4. Line 31 — Net Profit or (Loss): Subtract Line 30 from Line 29. If the number is positive, you have a net profit; if negative, you have a net loss and must check either Box 32a (All investment is at risk) or Box 32b (Some investment is not at risk).

Schedule C Line	Description	Example: Independent Electrician (2026)	How It Affects Line 31
Line 1	Gross receipts or sales	$142,000	Starting top-line revenue
Line 4	Cost of goods sold (Part III materials)	($28,500)	Reduces gross receipts
Line 7	Gross income	$113,500	Revenue after direct job materials
Line 9	Car and truck expenses (14,000 business miles @ 2026 IRS rate)	($10,150)	Operating deduction
Lines 8, 10–27a	Tools, GL insurance, licensing, software, phone, CPA fees	($18,350)	Operating deductions
Line 28	Total expenses	($28,500)	Subtracted from Line 7
Line 29	Tentative profit	$85,000	Profit before home office
Line 30	Business use of home (200 sq ft simplified method)	($1,000)	Subtracted from Line 29
Line 31	Net profit or (loss)	$84,000	Flows to Schedule 1, Schedule SE, and Form 8995

Where does Schedule C Line 31 flow on your Form 1040 tax return?

Once you calculate Line 31, you do not leave it on Schedule C. The IRS instructions direct you to copy that exact number to three separate places on your federal tax return, each triggering a different calculation:

1. Schedule 1 (Form 1040), Line 3 — Business Income or (Loss)

Your Line 31 net profit transfers directly to Schedule 1, Part I, Line 3, which then combines with any other additional income and lands on Form 1040, Line 8. From there, it becomes part of your Total Income (Line 9) and Adjusted Gross Income (Line 11).

2. Schedule SE (Form 1040), Line 2 — Self-Employment Tax

If your combined net earnings from self-employment are $400 or more, your Schedule C Line 31 profit flows to Schedule SE, Part I, Line 2. Here is where the 92.35% rule takes effect:

• On Schedule SE Line 4a, you multiply your Line 31 net profit by 0.9235 (92.35%). Why? Because employees do not pay Social Security and Medicare tax on the 7.65% FICA share their employer pays for them (100% - 7.65% = 92.35%). Multiplying Line 31 by 92.35% puts a self-employed person on equal footing with a W-2 worker.
• You then calculate 15.3% self-employment tax on that 92.35% figure (12.4% Social Security up to the $184,500 wage base in 2026, plus 2.9% Medicare on all net earnings).
• Finally, 50% of your Schedule SE tax flows back to Schedule 1, Part II, Line 15 as an above-the-line deduction, reducing your Adjusted Gross Income! You can walk through the full math in Schedule SE explained or test your own numbers in the self-employment tax calculator.

3. Form 8995 or Form 8995-A — 20% Qualified Business Income (QBI) Deduction

For most sole proprietors below the statutory taxable-income phaseout thresholds, a positive Schedule C Line 31 also serves as the base for the Section 199A Qualified Business Income (QBI) deduction (up to 20% of net qualified business income after deducting the deductible half of self-employment tax and self-employed health insurance).

What happens if Schedule C Line 31 is negative (a net business loss)?

When your legitimate operating expenses on Line 28 exceed your gross income on Line 7, Line 31 is a negative number (written in parentheses on the form). Two important rules apply whenever Line 31 shows a net loss:

1. Notice how Line 30 behaves during a loss: If you use the simplified method for the home office deduction on Line 30, it cannot create or increase a net loss on Line 31; if you use Form 8829 (actual expenses), unallowed home office expenses carry forward to the next tax year rather than enlarging the current year’s Schedule C loss.
2. Line 32a vs. Line 32b (At-Risk Rules): You cannot enter a net loss on Line 31 without checking either Box 32a or Box 32b:
   • Check Box 32a (All investment is at risk) if all the money you have invested in the business is your own cash, property, or recourse debt for which you are personally liable. When Box 32a is checked, your negative Line 31 flows to Schedule 1 Line 3 and can offset W-2 wages, a spouse’s income, or other ordinary income on your joint Form 1040 (subject to the Section 461(l) excess business loss threshold for very large losses).
   • Check Box 32b (Some investment is not at risk) only if part of your business financing comes from nonrecourse loans, stop-loss agreements, or borrowed funds where you have no personal liability. Checking 32b requires filing Form 6198 (At-Risk Limitations) to determine how much of the loss is currently deductible.

Why do mortgage lenders look at Schedule C Line 31 instead of Line 1?

Every year, thousands of profitable contractors and freelancers are shocked when a mortgage loan officer tells them they “don’t make enough income to qualify for a home loan” despite bringing in $150,000 or $200,000 in gross receipts.

Under Fannie Mae (Selling Guide B3-3.2-01) and Freddie Mac underwriting guidelines, mortgage underwriters ignore Line 1 (Gross receipts) and start their qualifying income calculation at Schedule C Line 31 (Net profit or loss) across your last two filed federal tax returns. Every aggressive write-off that lowered your Line 31 to save taxes also lowered the qualifying income the bank sees — with four critical add-backs that a good underwriter will restore to your Line 31 figure:

Schedule C Line Item	Added Back to Line 31 for Mortgage Qualifying?	Why Underwriters Add It Back
Line 13 — Depreciation and Section 179	Yes (+)	Paper non-cash expense; money did not leave your bank account that year
Line 12 — Depletion	Yes (+)	Non-cash accounting allowance
Line 30 — Business use of home	Yes (+)	Your personal housing payment is already counted in your debt-to-income ratio
Line 9 — Business miles (Depreciation portion)	Yes (+)	In 2026, the IRS designates a specific cents-per-mile depreciation component inside the standard mileage rate that underwriters can add back per business mile on Line 44a
Line 24b — Deductible meals	Subtracted (-)	Underwriters subtract the non-deductible 50% portion of business meals

Because every business mile reported in Part IV (Line 44a) carries an IRS-published depreciation component that mortgage underwriters can add back on top of Line 31, keeping a clean mileage log and separating depreciation on Line 13 gives you the best of both worlds: lower taxable income on Line 31 and higher qualifying income for a mortgage.

How do you keep your Line 31 accurate all year without spreadsheets?

Waiting until April to total twelve months of invoices and receipts guarantees two bad outcomes: either you miss legitimate deductions (inflating Line 31 and overpaying the 15.3% self-employment tax + income tax), or you have no idea what your quarter-by-quarter Line 31 looks like for Form 1040-ES quarterly estimated payments.

In Keel, every paid client invoice feeds your gross receipts, every scanned receipt is tagged to its exact IRS Schedule C Part II line item, and every business drive calculates your Line 9 mileage deduction automatically — so you can see your live projected Schedule C Line 31 net profit on your iPhone or in your private iCloud Workspace at any point in the year.

Frequently asked questions

Is Schedule C Line 31 my Adjusted Gross Income (AGI)?

No. Schedule C Line 31 is your net business profit or loss before personal adjustments. Your Line 31 figure flows to Schedule 1 Line 3 and then to Form 1040 Line 8, where it is combined with any other income and reduced by above-the-line adjustments — such as half of your self-employment tax, self-employed health insurance premiums, and SEP-IRA or Solo 401(k) contributions — to arrive at your Adjusted Gross Income on Form 1040 Line 11.

Why is my Schedule SE tax based on 92.35% of Schedule C Line 31?

When you work as a W-2 employee, your employer pays half of your Social Security and Medicare taxes (7.65% of wages), and that employer-paid 7.65% is not treated as taxable wages to you. To give self-employed filers the same treatment, IRS Schedule SE Line 4a multiplies your Schedule C Line 31 net profit by 92.35% (100% - 7.65%) before applying the 15.3% self-employment tax rate.

Do I owe self-employment tax if Schedule C Line 31 is under $400?

If your combined net earnings from self-employment (after multiplying Schedule C Line 31 by 92.35%) are less than $400 for the tax year, you do not owe federal self-employment tax and do not need to file Schedule SE. However, you must still report the Schedule C Line 31 profit on your Form 1040 if you otherwise meet the federal filing requirement.

Can a negative number on Schedule C Line 31 reduce my W-2 taxes?

Yes, provided your business is operated with a genuine profit motive under Internal Revenue Code Section 183 (not a hobby) and your investment is at risk (Box 32a checked). A legitimate net business loss on Schedule C Line 31 transfers to Schedule 1 Line 3 as a negative number and reduces your other ordinary income, including W-2 wages from a day job or a spouse’s salary on a joint return.

Where do I find Schedule C Line 31 when applying for a mortgage or loan?

Line 31 is located near the bottom of Page 1 of IRS Form 1040 Schedule C (Profit or Loss From Business), directly below Line 30 (Expenses for business use of your home) and above Line 32 (At-risk checkboxes). Lenders and underwriters typically request the last two years of signed Form 1040 returns including both pages of Schedule C to average your Line 31 net profit plus eligible non-cash add-backs.

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