What Is a K-1 Tax Form? Complete 2026 Guide

A K-1 tax form (officially Schedule K-1) reports your share of income, deductions, credits, and other items from a partnership, S corporation, estate, or trust. If you’re a partner in a business, an S-corp shareholder, or a beneficiary of a trust or estate, you’ll receive a K-1 each year showing what to report on your personal tax return.

K-1s are a pass-through tax mechanism: the entity itself usually doesn’t pay federal income tax. Instead, the entity passes its income (or losses) through to the owners or beneficiaries, who report it on their own returns.

Types of K-1 forms

There are three main K-1 variants — the form number differs based on the entity:

Form	Entity type	Recipient
Form 1065 Schedule K-1	Partnerships, LLCs taxed as partnerships	Partners / LLC members
Form 1120-S Schedule K-1	S corporations	S-corp shareholders
Form 1041 Schedule K-1	Estates and trusts	Beneficiaries

Each form is structurally similar but the entity sends a different one based on its tax classification. The income each pass-through entity reports flows to specific lines on your personal Form 1040.

When do you receive a K-1?

K-1s are due to recipients by the 15th day of the 3rd month after the entity’s fiscal year end:

Calendar-year partnerships, S-corps: K-1 due March 15 (some get extensions to September 15)
Calendar-year trusts: K-1 due April 15 (extensions to September 30)

Many K-1s arrive late, which is one of the biggest pain points for taxpayers waiting to file. If you haven’t received your K-1 by mid-March, contact the entity’s accountant. You may need to file an extension on Form 4868 to wait for it.

What’s on a K-1?

A K-1 has many boxes (15+ on partnership K-1s, 17+ on S-corp K-1s), but the most common ones include:

Income items

Box 1: Ordinary business income (loss) — flows to Schedule E
Box 2: Net rental real estate income — Schedule E
Box 3: Other rental income — Schedule E
Box 5: Interest income — Schedule B
Box 6: Dividends (ordinary + qualified) — Schedule B
Box 8/9: Short-term and long-term capital gains — Schedule D
Box 10: Section 1231 gain (asset sales) — Form 4797

Deductions and credits

Box 12: Section 179 deduction
Box 13: Other deductions (interest expense, charitable contributions, etc.)
Box 15: Credits (foreign tax credit, low-income housing, etc.)
Box 16/17: Foreign transactions
Box 18: Tax-exempt income (like municipal bond interest)

Self-employment items

Box 14 (partnership K-1): Self-employment earnings — flows to Schedule SE
Most S-corp K-1 boxes do NOT generate self-employment tax (a major SE-corp advantage over LLC/partnership)

How K-1 income affects your tax return

Pass-through entity income gets added to all your other income on your personal return. Key points:

Tax bracket impact: K-1 income stacks on top of your wages, so a 75K W-2 plus 25K K-1 ordinary income puts you in the same bracket as a 100K W-2 earner.

Self-employment tax (15.3% Social Security + Medicare):

Partnership / LLC K-1 (Box 14): YES, you owe SE tax on Box 14 amounts
S-corp K-1: NO, S-corp distributions are NOT subject to SE tax (this is why S-corps are popular)
However, S-corp shareholders who actively work in the business MUST take “reasonable compensation” as W-2 wages first

State income tax: Most states require you to report K-1 income on your state return. If the partnership operates in multiple states, you may owe tax in each state where it has nexus.

Common K-1 traps

1. Receiving K-1s for entities you forgot about. Old startup equity? Real estate LP? They still send K-1s annually even when there’s no income.

2. Mismatched K-1 box vs Form 1040 line. Each box has a specific destination. Misreporting can trigger IRS notices. Tax software (TurboTax, H&R Block, FreeTaxUSA) handles K-1 entry automatically.

3. Phantom income. Partnerships can allocate income to you that you didn’t actually receive in cash. You owe tax on the allocated amount whether or not it was distributed. Check your partnership agreement.

4. Passive activity loss limits. Most rental real estate K-1 losses are limited if you don’t materially participate. Losses suspend and carry forward until you have passive income or sell the activity.

5. Late K-1s. As noted, K-1s frequently arrive after the personal filing deadline. File an extension (Form 4868) — it’s not optional unless you want to amend later.

Reporting K-1 on TurboTax / FreeTaxUSA / H&R Block

In most popular tax software:

Search for “K-1” or “Schedule K-1” in the income section
Select the K-1 type (Form 1065, 1120-S, or 1041)
Enter each box from your K-1 separately — the software maps them to the right 1040 lines
Some boxes have sub-items (like Box 13 codes); enter each code carefully

Most software supports multiple K-1s. If you’re a partner in 4 partnerships, enter 4 separate K-1s.

When you might owe more tax from a K-1

Common surprises:

Profits without distributions (allocated income exceeds cash payouts)
Recapture when an entity sells depreciated assets
Self-employment tax for active partners
Net investment income tax (NIIT) of 3.8% on certain K-1 items above income thresholds
State tax in states you’ve never lived in (multi-state partnership)

For these reasons, K-1 recipients often need to make estimated tax payments quarterly using Form 1040-ES.

Frequently asked questions

Q: Is a K-1 the same as a 1099? A: No. A 1099 reports income paid TO you as an independent contractor or other recipient. A K-1 reports your SHARE of an entity’s tax items as a partner, shareholder, or beneficiary. The IRS gets a copy of both.

Q: Do I need to file taxes if I only have K-1 income? A: Yes, if the K-1 shows positive net income. Even small amounts of K-1 income trigger a filing requirement (unlike wages where the standard deduction may cover small amounts).

Q: Can I e-file with K-1s? A: Yes, all major tax software supports e-filing returns with K-1s. The K-1 attaches to your return electronically.

Q: What if my K-1 is wrong? A: Contact the entity’s accountant or general partner immediately. If it’s a clear error, request an amended K-1. Don’t just adjust the numbers on your own return — that creates a mismatch with what the IRS received from the entity.

Q: Are K-1 distributions taxable? A: This is confusing: K-1 income allocated to you is what’s taxable. The cash distribution you actually receive isn’t a separate tax event for partnerships and S-corps (you’ve already been taxed on the allocated income). Trust K-1 distributions can be different — DNI (distributable net income) rules apply.

If you’re navigating K-1 income, these calculators help:

Tax Calculator — Estimate total federal tax with K-1 income included
Self-Employment Tax Calculator — For partnership K-1 Box 14 amounts
Capital Gains Tax Calculator — For K-1 capital gain boxes
Tax Bracket Calculator — See how K-1 income changes your bracket

The K-1 ecosystem is one of the more complex parts of US tax. When in doubt, consult a CPA familiar with pass-through entity taxation.