Can I Write Off Business Losses on My Personal Taxes?

Yes, you can generally write off business losses on your personal taxes if your business is a pass-through entity — a sole proprietorship, partnership, LLC, or S corporation. The loss flows to your Form 1040 and reduces income from wages, investments, and other sources. But the deduction has to survive a stack of tests: a profit-motive check, a material participation rule, an at-risk limit, and an annual cap on how much business loss can offset non-business income ($256,000 single / $512,000 joint for 2026). Miss any of them and the IRS can disallow the deduction, assess back taxes, and add a 20% accuracy-related penalty.

Which Business Structures Let Losses Reach Your 1040

The threshold question is whether your business is taxed as a pass-through. With a pass-through, the business itself pays no federal income tax; profits and losses flow to the owners’ personal returns. Sole proprietors report on Schedule C attached to Form 1040, and the IRS treats owner and business as a single taxpayer.1Internal Revenue Service. Sole Proprietorships Single-member LLCs work the same way unless they elect corporate treatment.2Internal Revenue Service. Single Member Limited Liability Companies

Multi-member LLCs and general partnerships file Form 1065, and each partner receives a Schedule K-1 showing their share of the loss. S corporations work the same way: shareholders take their allocated loss through a K-1. In both cases, the K-1 figures land on Schedule E of your personal return.

C corporations are the exception. A C corp is a separate taxpayer that files Form 1120 and pays tax at the corporate level. Its losses stay inside the corporate return; you can’t use them to offset your salary or investment income personally. For losses arising after 2017, C corp carrybacks are also unavailable except for certain farming losses.3Internal Revenue Service. Tax Cuts and Jobs Act: A Comparison for Businesses

Is It a Business or a Hobby?

Before anything else, the IRS wants to see that you’re actually trying to make money. Section 183 of the Internal Revenue Code limits deductions from activities not engaged in for profit.4Office of the Law Revision Counsel. 26 USC 183 – Activities Not Engaged in for Profit

There’s a safe harbor. If the activity shows a net profit in at least three of the last five tax years, it’s presumed to be a for-profit business. Horse breeding, training, showing, and racing get a looser standard: two out of seven years.4Office of the Law Revision Counsel. 26 USC 183 – Activities Not Engaged in for Profit Falling outside the safe harbor doesn’t automatically kill the deduction; it shifts the burden to you to show you’re running a real business. That means separate books, a business bank account, meaningful hours worked, and adjustments when things aren’t working.

Side businesses, creative pursuits, and small farming operations get the closest scrutiny here. Losses year after year with no visible move toward profitability invite reclassification.

Active or Passive Losses

Once the activity is a real business, the next question is how much time you spend on it. If you materially participate, the loss is active and can offset any income — wages, interest, capital gains. If you don’t, the loss is passive and can only offset passive income from other sources.5Internal Revenue Service. Topic No. 425, Passive Activities – Losses and Credits

Material participation has seven possible tests under the regulations, and you only need to pass one.6eCFR. 26 CFR 1.469-5T – Material Participation (Temporary) The cleanest is the 500-hour test: more than 500 hours of participation during the year. Others cover being essentially the only participant, participating more than 100 hours with nobody else doing more, and various prior-year and facts-and-circumstances paths. Whichever test you rely on, keep a contemporaneous log. A reconstruction cobbled together at tax time won’t hold up under audit.

Rental activities are treated as passive by default, no matter how many hours you put in. Landlords who actively participate can deduct up to $25,000 of rental losses against non-passive income, but that allowance phases out between $100,000 and $150,000 of modified adjusted gross income.7Internal Revenue Service. Instructions for Form 8582 (2025)

How Much of the Loss You Can Actually Deduct

Three limits stack on top of each other. You clear them in order, and a loss that gets stopped at one level doesn’t necessarily vanish — it usually carries forward.

At-Risk Rules

Under Section 465, you can only deduct losses up to what you could actually lose in the business. Your at-risk amount includes cash invested, the adjusted basis of contributed property, and borrowed money you’re personally liable for or have pledged personal assets against.8Office of the Law Revision Counsel. 26 USC 465 – Deductions Limited to Amount at Risk Non-recourse debt, where the lender can only reach business assets, generally doesn’t count.

Losses above your at-risk amount are suspended and carried forward. When you put in more cash or take on more personal liability, the suspended losses free up.

The Excess Business Loss Cap

After you clear at-risk and passive activity rules, Section 461(l) caps how much of your net business loss can offset non-business income (wages, investment returns) in a single year. For 2026 the cap is $256,000 for single filers and $512,000 for joint filers, indexed for inflation.9Cornell Law Institute. Definition: Excess Business Loss from 26 USC 461(l)(3) The 2025 figures were $313,000 and $626,000; the 2026 numbers reflect a legislative reset of the base amount after the provision was made permanent.

Anything above the threshold isn’t gone. It converts into a net operating loss that carries forward.

NOL Carryforward

When your business losses exceed all your other income for the year after the caps above, the result is a net operating loss. For losses arising after 2017, you carry an NOL forward indefinitely; carrybacks are gone except for farming losses.10Office of the Law Revision Counsel. 26 USC 172 – Net Operating Loss Deduction

There’s a further ceiling on use. In any future year, the NOL deduction can’t exceed 80% of taxable income calculated before the NOL itself. Carry forward $200,000, earn $100,000 next year, and you can offset $80,000. The remaining $120,000 carries into the following year.11Internal Revenue Service. Instructions for Form 172 (12/2024) A large NOL takes several years to absorb.

What a Loss Does to Self-Employment Tax

A Schedule C loss zeroes out self-employment tax on that activity, because SE tax runs on net earnings.12Internal Revenue Service. Topic No. 554, Self-Employment Tax If you run more than one business, a loss in one reduces the combined net earnings used for SE tax across all of them.13Internal Revenue Service. Instructions for Schedule SE (Form 1040) (2025)

That’s cash saved now, but it has a downside. SE tax funds Social Security and Medicare, and a year with no net earnings is a year you earn no Social Security credits. Benefits are calculated on your 35 highest-earning years, so a string of loss years leaves zeroes in that calculation. Schedule SE has optional methods that let you report a small amount of net earnings and pay a modest SE tax to preserve credits during loss years.

The Forms and Records

The forms depend on your structure, but the documentation demand is the same everywhere: proof for every dollar of income and expense.

Beyond the forms, keep a mileage log with dates, destinations, and business purpose; home office measurements if you claim that deduction; and receipts or bank statements for every expense. Vehicle expenses in particular have specific recordkeeping rules, and rough estimates don’t survive an audit.15Internal Revenue Service. Instructions for Schedule C (Form 1040) (2025)

Audit Exposure and Penalties

A business loss isn’t inherently suspicious, but certain patterns draw the IRS’s attention. Schedule C filers reporting losses face audit rates roughly double those of profitable filers. Deductions that look disproportionate to income get flagged, and repeated losses without a visible profit motive are the classic hobby loss trigger.

If a claimed loss is disallowed, you owe the back taxes plus a 20% accuracy-related penalty on the underpayment.16Office of the Law Revision Counsel. 26 USC 6662 – Imposition of Accuracy-Related Penalty on Underpayments On a $30,000 disallowed loss in the 22% bracket, that’s roughly $6,600 in tax plus a $1,320 penalty, before interest. The penalty applies where the underpayment results from negligence, a substantial understatement of income, or transactions lacking economic substance.

The best defense is documentation showing genuine profit intent: a written business plan, evidence of expertise, time logs, and records of changes you made when results were poor. Legitimate, documented losses are exactly what the code contemplates.

One Change That Affects 2026 Planning

Through 2025, the Section 199A qualified business income deduction let pass-through owners deduct up to 20% of their qualified business income. That deduction expired on December 31, 2025, and is not available for 2026.17Internal Revenue Service. Qualified Business Income Deduction Two effects on loss planning: profitable pass-throughs now face a higher effective rate without the 20% deduction, changing the math on when to accelerate or defer expenses; and any negative QBI carrying forward from prior years no longer produces a deduction under the old mechanism. Congress could revive Section 199A retroactively, but 2026 returns should be prepared without it.