A partnership pays no income tax. It files Form 1065, hands each partner a Schedule K-1, and the partner pays the tax on that share. No one withholds anything along the way. If you expect to owe $1,000 or more when you file, you make the four estimated payments yourself.
How partnership income reaches you
Each year the partnership reports its income, deductions, gains, and losses on Form 1065 and sends every partner a Schedule K-1 with that partner's share. A multi-member LLC taxed as a partnership works the same way.
The K-1 is not one number. Box 1 is your share of ordinary business income. Box 4 holds guaranteed payments, with 4a for services and 4b for the use of capital. Rental income, interest, dividends, and capital gains each get their own box because each is taxed under its own rules on your return.
You owe tax on your distributive share whether or not the partnership paid you any cash. Box 19 shows what it actually distributed, and the two figures are often far apart. Partners are not employees and get no W-2, which is why nothing is withheld.
Self-employment tax on a partner's share
A general partner's share of ordinary business income, plus any guaranteed payments for services, is net earnings from self-employment. The partnership reports the figure in box 14, code A. Schedule SE taxes 92.35% of that figure at 15.3%. Of that rate, 12.4% is Social Security, which stops at the annual wage base, and 2.9% is Medicare, which never stops. The Additional Medicare Tax adds 0.9% once wages and self-employment income together pass $200,000 for a single filer or $250,000 for a married couple filing jointly.
A limited partner owes self-employment tax only on guaranteed payments for services. Who counts as a limited partner here follows section 1402(a)(13), not the label in the partnership agreement. For an LLC member the answer turns on how active the member is in the business, and the courts are still drawing that line. Compare box 14 with the work you actually do, and ask the preparer who signed the Form 1065 how the figure was set.
Our self-employment tax calculator shows the size of this tax on a single figure.
The K-1 arrives after every deadline
Form 1065 is due March 15 for a calendar-year partnership, and a six-month extension moves it to September 15. Many partnerships take the extension, so many partners see their K-1 in September. By then all four estimated tax deadlines for that year have passed.
So you estimate during the year from what the partnership can tell you. Interim books from the bookkeeper, the distributions you have received, and last year's K-1 are the usual sources. Pay on that basis and settle the difference when the real K-1 lands.
The safe harbor rule makes that workable. Pay 100% of last year's total tax, or 110% if last year's AGI was over $150,000, in four equal installments, and no underpayment penalty applies however the current year turns out. The figure comes off last year's return, not this year's books.
When last year's K-1 is the wrong guide
Safe harbor keeps the penalty away. It does not settle the bill. A partner whose share jumped this year can pay last year's number all four quarters, owe no penalty, and still write a large check in April. Set the difference aside each quarter as the books come in.
A partner whose share fell has the opposite problem and overpays every quarter against a tax that no longer applies. Paying 90% of the current year's expected tax instead is allowed and lowers each payment, but it means estimating the current year closely. When the income also arrived late in the year, the annualized income method sizes each installment to what you had actually earned by that deadline.
Phantom income and tax distributions
Phantom income is profit the partnership allocated to you and kept, usually to fund payroll, inventory, or debt payments. You owe tax on it in the year of allocation, and the quarterly payment comes out of your own account.
Many partnership agreements carry a tax distribution clause that requires the partnership to distribute enough cash for each partner to cover the tax on the allocated share. Read your agreement before the first deadline. Without that clause, the tax on retained profit comes out of your other income.
Deductions that lower the estimate
Three deductions shrink the number before you pay it. Half of your self-employment tax comes off as an adjustment to income, so the 15.3% costs less than it looks.
The qualified business income deduction removes up to 20% of qualified business income from taxable income. Income limits apply, and specified service businesses such as law, accounting, and consulting face tighter rules above them. The partnership reports what you need in box 20, code Z.
Health insurance the partnership paid for you appears in box 13, code M. You deduct it as self-employed health insurance on your own return.
State tax adds another layer
A partnership with nonresident partners often withholds state tax for them or files a composite return that pays it, and either one lowers what that partner sends the state directly. Many states also let the partnership elect a pass-through entity tax, where the entity pays the state tax and the partner takes a credit. Both change your quarterly number, and neither shows on the federal K-1, so ask the partnership which states it pays into before you set state payments. Our guide to state estimated taxes covers the general rules. S corporation owners follow a separate set of rules, covered in estimated taxes on S corporation income.
Put K-1 income into a real quarterly estimate
EstimatedTax.com takes your partnership share alongside wages and every other kind of income, runs both official IRS methods on the same numbers, and recommends the lower payment.
Sources: IRS Partnerships · IRS Self-Employment Tax · Partner's Instructions for Schedule K-1 (Form 1065) · Instructions for Form 1065