U.S. · Tax forms
Schedule SE line 13, half your self-employment tax.
Line 12 times 50 percent, on its way to Schedule 1.
Line 13 is the “Deduction for one-half of self-employment tax”: multiply line 12 by 50% (0.50) and enter the result on Schedule 1 (Form 1040), line 15. It is not an expense on Schedule C or Schedule F.
Look up a line item
Result
Line 12, line 13 and where they go (2025 form)
| Item | Meaning | What the IRS says |
|---|---|---|
| Line 10 | Social security part | Multiply the smaller of line 6 or line 9 by 12.4% |
| Line 11 | Medicare part | Multiply line 6 by 2.9% (0.029) |
| Line 12 | Self-employment tax | Add lines 10 and 11; enter on Schedule 2 (Form 1040), line 4, or Form 1040-SS, Part I, line 3 |
| Line 13 | Deduction for one-half of self-employment tax | Multiply line 12 by 50% (0.50); enter on Schedule 1 (Form 1040), line 15 |
| Form 1040-SS | Filers of 1040-SS | The instructions say to skip line 13 |
| Schedule C / F | Not a business expense | The Schedule F instructions say not to deduct self-employment tax as a tax on that schedule; the one-half deduction is on Schedule 1, line 15 |
| Earned income credit | Worksheet B | If you must file Schedule SE, enter one-half of the self-employment tax on Part 1, line 1d, of Worksheet B |
What the deduction does
Line 13 takes half of the line 12 self-employment tax and sends it to Schedule 1, line 15, where it is an adjustment in figuring income. It does not change the line 12 tax itself, and it is not subtracted from your net profit on Schedule C line 31 or Schedule F line 34.
Where the instructions mention it
The Schedule SE instructions have no explanatory paragraph under the “Line 13” heading beyond the note to skip the line if you are filing Form 1040-SS; the Additional Medicare Tax discussion follows it. The deduction itself is described in the Schedule C instructions, which say you can deduct one-half of your self-employment tax on Schedule 1 (Form 1040), line 15.
Do not confuse it with the Additional Medicare Tax
A 0.9% Additional Medicare Tax may apply when the total on line 6 of all your Schedules SE exceeds a threshold that depends on filing status. It is figured on Form 8959 and is separate from the one-half deduction. Line 13 uses only the line 12 amount.
Worked example
Tara has self-employment tax of $9,180 on line 12. Line 13 is $9,180 × 0.50 = $4,590, entered on Schedule 1, line 15. Names and figures are made up.
More line pages in this set
Related lines: Schedule SE Line 8a, Schedule C Line 31.
Sources
- Schedule SE (Form 1040) (2025): The printed line 10 to 13 wording and arithmetic. Read November 2, 2026.
- Instructions for Schedule SE (Form 1040) (2025): The Line 13 heading note and the Additional Medicare Tax discussion. Page last reviewed or updated April 30, 2026. Read November 2, 2026.
- Instructions for Schedule C (Form 1040) (2025): The statement that one-half of self-employment tax is deducted on Schedule 1, line 15, and the Worksheet B reference. Page last reviewed or updated April 30, 2026. Read November 2, 2026.
- Instructions for Schedule F (Form 1040) (2025): The line 29 note that self-employment tax is not deducted as a tax on that schedule. Page last reviewed or updated April 30, 2026. Read November 2, 2026.
Tax year 2025 instructions (page last reviewed or updated April 30, 2026). The line labels were read from the Schedule SE (Form 1040) PDF the IRS had posted on the date read, which is the 2025 edition; line numbers can shift between years, so check them against the form for your tax year. Names and figures in worked examples are made up.
Frequently asked questions
What is Schedule SE line 13?
The deduction for one-half of self-employment tax: line 12 multiplied by 50% (0.50).
Where does the line 13 amount go?
The form says to enter it on Schedule 1 (Form 1040), line 15.
Is it a Schedule C business expense?
No. The Schedule F instructions say self-employment tax is not deductible as a tax on that schedule but that you can deduct one-half of it on Schedule 1, line 15.
Do Form 1040-SS filers use line 13?
No. The instructions say if you are filing Form 1040-SS, skip this line.
Is the Additional Medicare Tax part of line 13?
No. The 0.9% Additional Medicare Tax is figured on Form 8959; line 13 is only half of the line 12 amount.
Not tax advice
This page summarizes IRS instructions, mostly written for the people who prepare the form, and is not tax, legal or financial advice. A CPA or an enrolled agent can confirm what a line means for your return. Everything runs in your browser; nothing you enter is sent anywhere.