Updated October 17, 2026. Quick answer: Line 10 is reserved for future use, so there is nothing to enter. Line 11 is the Additional Medicare Tax and it comes from Form 8959. The instructions point you to that form when your 2025 wages and any self-employment income were above a threshold for your filing status.
Form lines read one part at a time: Form 8959 Part I, Form 8959 Part III and Form 8959 Parts IV and V.
Schedule 8812 (child tax credit and additional child tax credit) for 2025, read line by line: Schedule 8812 lines 21 to 26.
Related reading on this site: Form 8959 Additional Medicare Tax.
Line 10: reserved
The caption for line 10 reads “Reserved for future use”. The instructions say “Line 10 has been reserved for future use.” There is no amount to find or enter on this line.
Line 11: when to look at Form 8959
The caption for line 11 reads “Additional Medicare Tax. Attach Form 8959”. The instructions say “See Form 8959 and its instructions if the total of your 2025 wages and any” self-employment income was more than the amount for your filing status:
For married filing separately, “$125,000 if married filing separately;”
For married filing jointly, “$250,000 if married filing jointly;”
For single, head of household, or qualifying surviving spouse, “$200,000 if single, head of household, or qualifying surviving spouse.”
Railroad retirement is covered too: “Also see Form 8959 if you had railroad retirement (RRTA) compensation that was more than the amount just listed that applies to you.”
When your employer withheld too much
The instructions add a case for joint filers: “If you are married filing jointly and either you or your spouse had wages or RRTA compensation of more than $200,000, your employer may have withheld Additional Medicare Tax even if you don’t owe the tax.” They continue “In that case, you may be able to get a refund of the tax withheld.” The Additional Medicare Tax is explained on the Additional Medicare Tax page.
Where the number comes from
The line 11 amount comes from Form 8959, which is attached to the return. Schedule 2 does not figure it. For the withholding side of the same tax, the instructions say “See the Instructions for Form 8959 to find out how to report the withheld tax on Form 8959.”
Where it goes next
Line 11 is one of the lines added on line 21, which reads “Add lines 4, 7 through 16, 18, and 19. These are your total other taxes.” and then “Enter here and on Form 1040 or 1040-SR, line 23”. Line 10 is inside the range of that sum but has nothing to add. The next line, the net investment income tax, is a separate tax on a separate form, and it is explained on the net investment income tax page. The whole schedule is on the Schedule 2 (Form 1040) page and the return itself is on the Form 1040 page.
Edition and line numbers
This page reads the 2025 Schedule 2 (Form 1040) and the 2025 Form 1040 instructions, the current files irs.gov served on 2026-10-17. They are the files for the tax year 2025 return, filed in 2026. The schedule says “Attach to Form 1040, 1040-SR, or 1040-NR.” Its line instructions are part of the Form 1040 instructions, under the heading “Instructions for Schedule 2”. Check the tax year printed on the schedule you are filling in and use the line numbers on that year’s schedule, because a different year’s schedule can number or word its lines differently.
Common mistakes
- Entering something on line 10. The instructions say “Line 10 has been reserved for future use.”
- Using the wrong threshold for the filing status. The instructions list “$250,000 if married filing jointly;” and “$125,000 if married filing separately;”.
- Assuming withholding means the tax is owed. The instructions say “your employer may have withheld Additional Medicare Tax even if you don’t owe the tax.”
Related: Additional Medicare Tax, net investment income tax, and Form 1040.
Sources
- Instructions for Form 1040 and Form 1040-SR (2025): https://www.irs.gov/pub/irs-pdf/i1040gi.pdf
- Schedule 2 (Form 1040), Additional Taxes (2025): https://www.irs.gov/pub/irs-pdf/f1040s2.pdf
Read from the IRS documents linked above on October 17, 2026. General information, not tax advice. Your own facts decide the outcome, and a preparer, the account provider or the IRS is the right place to confirm anything consequential.