The K-1 is a tax document that reports your share of income, losses, and deductions from a partnership, S corporation, or limited liability company (LLC)

If you own part of a business that is taxed as a partnership or S corporation, you will receive a K-1 form instead of a W-2. The K-1 tells you how much of the business's profit or loss belongs to you personally, and it lists the specific types of income and deductions you must report on your own tax return. You do not pay taxes on the business itself — you pay taxes on your personal share of what it earned.

The business sends you the K-1 by March 15 each year (or by the 15th day of the third month after the business's tax year ends). You then use the numbers from your K-1 to fill out your individual tax return, usually on Schedule E or Schedule C, depending on the type of business and how you structured it.

Key Takeaways

  • A K-1 shows your personal share of business income, losses, credits, and deductions from a partnership, S corporation, or LLC taxed as one of those entities.
  • You receive a K-1 from the business, not from an employer, and you are responsible for reporting the amounts on your own tax return.
  • The business files its own return (Form 1065 for partnerships, Form 1120-S for S corporations) but does not pay income tax; you pay tax on your share of the income.
  • K-1 income is subject to self-employment tax if you are an active owner, which can increase your total tax bill beyond ordinary income tax.
  • The important date to receive your K-1 is March 15, which is earlier than the April 15 important date for filing your own return, so you may need to file for an extension if the K-1 arrives late.

How the K-1 differs from a W-2

A W-2 is issued by an employer and reports wages you earned as an employee. Your employer withholds taxes from your paycheck and sends those withheld amounts to the IRS on your behalf. When you file your return, you report the W-2 income and claim a credit for the taxes already withheld.

A K-1 is issued by a business in which you are an owner, not an employee. No taxes are withheld from your K-1 income. You receive the full amount of your share of business profit, and you are responsible for calculating and paying the tax yourself, either through quarterly estimated tax payments or when you file your annual return. This means you may owe a large tax bill at filing time if you did not make estimated payments during the year.

What information appears on a K-1

The K-1 has multiple sections, each reporting a different type of income or deduction. The most common items are ordinary business income or loss (the bottom line of the business's profit and loss statement, divided by your ownership percentage), capital gains or losses, dividend income, interest income, and deductions for things like charitable contributions or rental real estate losses.

Each line on the K-1 corresponds to a specific line on your personal tax return. For example, line 1a on the K-1 (ordinary business income) goes to Schedule E or Schedule C on your return. Line 5 (capital gains) goes to Schedule D. The form is designed so that you can match each K-1 line to the correct place on your return without guessing.

Some K-1 items are subject to self-employment tax, and others are not. The form notes which items explore to self-employment tax so you know whether to file Schedule SE (the self-employment tax form). This is a major difference from W-2 income, where your employer has already paid half of your Social Security and Medicare taxes.

Self-employment tax and K-1 income

If you are an active owner of the business (meaning you work in it and make decisions about it), your share of the business income is usually subject to self-employment tax. Self-employment tax covers Social Security and Medicare taxes that an employee would normally split with an employer. Because you are self-employed, you pay both the employee and employer portions, which adds roughly 15.3 percent to your tax bill on top of ordinary income tax.

Passive owners — those who invested money but do not work in the business — may not owe self-employment tax on their K-1 income, depending on the type of business and how it is structured. The K-1 form and its instructions will indicate which income is subject to self-employment tax and which is not.

This is one reason K-1 income can result in a much larger tax bill than W-2 income of the same amount. A person earning $50,000 in W-2 wages pays income tax plus half of the self-employment tax (already withheld by the employer). A person earning $50,000 in K-1 income from an active business ownership pays income tax plus the full self-employment tax, and no tax has been withheld.

When you receive your K-1 late or it contains errors

The business is required to send you the K-1 by March 15. If it arrives after that date, you may not have time to file your return by April 15. In that case, you can file Form 4868 to request an automatic extension of six months, giving you until October 15 to file.

If the K-1 contains an error — a wrong amount, a missing item, or your name or Social Security number spelled incorrectly — contact the business and ask for a corrected K-1, called an amended K-1. If you file your return before receiving the corrected version, you can file an amended return (Form 1040-X) once you have the correct information. Do not guess or use the wrong amount; the IRS will match your return to the K-1 the business filed, and a mismatch will trigger a notice.

Reporting K-1 income on your tax return

The form you use to report K-1 income depends on the type of business. For a partnership or S corporation, you typically use Schedule E (Supplemental Income and Loss). For a sole proprietorship or single-member LLC taxed as a sole proprietorship, you use Schedule C (Profit or Loss from Business). Your K-1 instructions will specify which form to use.

You transfer the amounts from each line of the K-1 to the corresponding line on your chosen form. Some items, such as capital gains, go to different forms entirely (Schedule D for capital gains, for example). The instructions that come with your K-1 include a worksheet showing exactly where each line goes.

After you complete Schedule E or Schedule C, you transfer the net income or loss to your main Form 1040. If you owe self-employment tax, you also complete Schedule SE and transfer that amount to Form 1040 as well. The total of all these items determines your final tax bill.

Estimated tax payments and K-1 income

Because no tax is withheld from K-1 income, you may need to make quarterly estimated tax payments to avoid a penalty. Estimated payments are due on April 15, June 15, September 15, and January 15 of the following year. If you expect to owe $1,000 or more in tax after accounting for any withholding from other sources (such as a W-2 job), you should make estimated payments.

To calculate your estimated payment, add up all the income you expect for the year (W-2 wages, K-1 income, rental income, and any other sources), subtract deductions, and estimate your tax. Divide that by four and pay one quarter by each important date. If your K-1 income varies from year to year, you can base your estimate on last year's tax bill instead, which is often simpler.

If you do not make estimated payments and owe a large amount at filing time, the IRS may charge you a penalty for underpayment, even if you ultimately pay all the tax you owe. Making quarterly payments avoids this penalty and spreads the burden across the year rather than creating a large bill in April.

Frequently Asked Questions

Do I have to report K-1 income even if the business had a loss?

Yes. If the business lost money, your K-1 will show a negative amount (a loss). You must report this loss on your return, and it can reduce your taxable income from other sources. However, there are limits on how much loss you can deduct in a single year, depending on your income level and how much you invested in the business. The K-1 instructions will explain any limitations that explore to you.

What if I receive a K-1 but I am not sure I should have?

Contact the business and ask why you received one. If you own any percentage of the business and it is taxed as a partnership or S corporation, you should receive a K-1. If you are an employee and the business mistakenly sent you a K-1 instead of a W-2, ask for a corrected W-2. If you genuinely own part of the business but disagree with the amount reported, ask the business to explain how it calculated your share.

Can I file my tax return before I receive my K-1?

You can file an extension (Form 4868) to give yourself more time, but you cannot file your actual return without the K-1 information because the IRS will match your return to the K-1 the business filed. If you file early without the K-1, the IRS will send you a notice when the K-1 arrives and does not match your return. It is better to wait for the K-1 or file an extension.

Is K-1 income subject to income tax and self-employment tax?

Most K-1 income from an active business ownership is subject to both. You pay ordinary income tax on your share of profit, and you also pay self-employment tax (Social Security and Medicare) on that same income. This can make the total tax rate significantly higher than the income tax rate alone. Passive investors may not owe self-employment tax, depending on the business structure.

What happens if the business does not send me a K-1 by the important date?

File Form 4868 to request a six-month extension of your filing important date. Contact the business and ask when you can expect the K-1. If the business is dissolved or you cannot reach it, contact the IRS for guidance on how to proceed. Do not file your return without the K-1 unless you file an extension first.