Schedule SE is a one-page form, but the numbers on it touch three other parts of your return, so working through it in order matters. To fill out Schedule SE, start with the net profit figure from your Schedule C, F, or partnership K-1, reduce it by 92.35%, apply the 12.4% Social Security tax up to the annual wage base and the 2.9% Medicare tax with no cap, and then move the total to Schedule 2 and half of it to Schedule 1 as a deduction. Everything below is the same process at line-level detail.
What to Have in Front of You
Schedule SE doesn’t generate its own income figure. It pulls one from whichever business form you’ve already completed. Sole proprietors take net profit from Schedule C, line 31. Farmers use Schedule F, line 34. Partners look at Box 14, code A on the Schedule K-1 from Form 1065.1Internal Revenue Service. Partner’s Instructions for Schedule K-1 (Form 1065) (2025) Finish those first.
You’ll also want any W-2s from the same tax year. Wages paid through a regular job count against the Social Security wage base before your self-employment earnings do, and Schedule SE has a line for entering them.
Two situations look like they belong on Schedule SE but don’t. If Box 13 of your W-2 is marked “Statutory employee,” that income goes on Schedule C but stops there. Your employer already paid Social Security and Medicare on those wages.2Internal Revenue Service. Instructions for Schedule SE (Form 1040) (2025) Church employees whose employer opted out of FICA follow a different rule: self-employment tax applies once church wages exceed $108.28 for the year.3Internal Revenue Service. Publication 517 (2025), Social Security and Other Information for Members of the Clergy and Religious Workers
Working Through Part I
Most filers only need Part I. The lines run in order.
Line 1a is for net farm profit or loss from Schedule F, or from Box 14, code A of a farming partnership K-1. Skip it if you don’t farm. Line 1b is for a Conservation Reserve Program payment from the USDA, if you received one.
Line 2 is where most self-employed filers write their main number: net nonfarm profit or loss from Schedule C, line 31, or from Box 14, code A of a non-farming K-1.4Internal Revenue Service. 2025 Schedule SE (Form 1040)
Line 3 combines lines 1a, 1b, and 2.
Line 4 does the one adjustment that catches people who haven’t filed the form before. Multiply line 3 by 92.35% (0.9235). The reason: employees pay Social Security and Medicare only on wages, not on the employer’s matching share, and this factor mirrors that treatment for someone paying both halves.5Internal Revenue Service. Topic No. 554, Self-Employment Tax
If line 4 comes out under $400, you’re done. No self-employment tax is owed and Schedule SE generally doesn’t need to be filed.6Internal Revenue Service. 2025 Instructions for Schedule SE (Form 1040)
The Social Security Piece
Schedule SE splits the calculation because Social Security tax stops at a yearly cap and Medicare tax doesn’t. For 2026, the Social Security wage base is $184,500.7Social Security Administration. 2026 Cost-of-Living Adjustment (COLA) Fact Sheet You pay the 12.4% Social Security portion only on earnings up to that ceiling.8Office of the Law Revision Counsel. 26 USC 1401 – Rate of Tax
If your line 4 is at or below $184,500 and you had no W-2 wages, the Social Security tax is line 4 times 12.4%.
W-2 wages complicate that. Enter your total Social Security wages from your W-2s on line 8a. The form subtracts those wages from $184,500 to figure out how much room is left for self-employment earnings under the cap. If your W-2 wages already meet or exceed $184,500, the Social Security portion of your self-employment tax is zero.9Internal Revenue Service. Self-Employment Tax (Social Security and Medicare Taxes) The Social Security tax lands on line 10.
The Medicare Piece
Medicare has no ceiling. Every dollar on line 4 is subject to the 2.9% Medicare tax, no matter what your W-2 wages were. That calculation goes on line 11.
Line 12 and the Deduction on Line 13
Add line 10 and line 11. The result on line 12 is your total self-employment tax for the year. As a rough example, $80,000 of net profit becomes $73,880 after the 92.35% adjustment, and 15.3% of $73,880 is $11,303.64.
Line 13 is the deduction for one-half of your self-employment tax. Multiply line 12 by 50% and enter the result. This adjusts your income whether you itemize or take the standard deduction.
Where the Numbers Go on Form 1040
Schedule SE feeds two different places on your return, and mixing them up is a common error.
- Line 12 (the tax) goes to Schedule 2 (Form 1040), line 4. It adds to your total tax.4Internal Revenue Service. 2025 Schedule SE (Form 1040)
- Line 13 (half of that tax, as a deduction) goes to Schedule 1 (Form 1040), line 15. It reduces your adjusted gross income.
One number increases what you owe; the other trims your taxable income. Both come from the same Schedule SE, and both are supposed to be there.
If Your Income Is High Enough for Additional Medicare Tax
An extra 0.9% Medicare tax applies once combined wages and self-employment income cross these thresholds, which have not been indexed since 2013:10Internal Revenue Service. Instructions for Form 8959
- Single or head of household: $200,000
- Married filing jointly: $250,000
- Married filing separately: $125,000
This tax is not calculated on Schedule SE. Take the self-employment income from Schedule SE, Part I, line 6, and carry it to Form 8959, line 8. Form 8959’s result flows to Schedule 2 alongside your regular self-employment tax, and any Additional Medicare Tax already withheld from W-2 wages gets credited on the same form.11Internal Revenue Service. Questions and Answers for the Additional Medicare Tax
When Part II Is Worth Looking At
Part II lets filers with unusually low earnings report a higher figure than they actually made, so they can pick up Social Security work credits for the year. It costs more in tax but builds the benefits record.
The farm optional method is available if gross farm income was $10,860 or less, or net farm profit was under $7,240. You report two-thirds of gross farm income, capped at $7,240, in place of your actual net profit.12Internal Revenue Service. Farmer’s Tax Guide
The nonfarm optional method is available if net nonfarm profit was under $7,840 and also under 72.189% of gross nonfarm income, and you were regularly self-employed (net earnings of $400 or more in at least two of the prior three years). It can only be used five tax years in a lifetime, consecutive or not.2Internal Revenue Service. Instructions for Schedule SE (Form 1040) (2025)
Most filers skip Part II entirely.
Attaching Schedule SE to Your Return
Schedule SE is filed with Form 1040, not separately. Tax software links it automatically when you e-file. On paper, include it with the rest of your schedules and mail the return to the IRS processing center for your state. Anyone with net self-employment earnings of $400 or more is required to file it.13Office of the Law Revision Counsel. 26 USC 6017 – Self-Employment Tax Returns