Updated October 17, 2026. Quick answer: Line 11 is a credit for too much social security or tier 1 railroad retirement tax withheld when you had more than one employer. The number comes from your Forms W-2 and the limits in the Form 1040 instructions, figured separately for you and your spouse. The result is added into line 15.
Form lines read one part at a time: Form 8959 Part III.
Schedule 8812 (child tax credit and additional child tax credit) for 2025, read line by line: Schedule 8812 lines 21 to 26.
What line 11 is
The schedule captions it “Excess social security and tier 1 RRTA tax withheld”, in Part II, “Other Payments and Refundable Credits”. The instructions explain when the problem arises: “If you, or your spouse if filing a joint return, had more than one employer for 2025 and total wages of more than” the amount the instructions print, “too much social security or tier 1 railroad retirement (RRTA) tax may have been withheld.”
What goes on line 11 and where the number comes from
The instruction for the amount reads: “You can take a credit on this line for the amount withheld in excess of $10,918.20.” The wage threshold is printed in the same paragraph: “total wages of more than $176,100”. For the withholding figure on a wage statement, see the W-2 box 4 social security tax withheld page.
The instructions limit the credit in two ways. First, “But if any one employer withheld more than $10,918.20, you can’t claim the excess on your return.” In that case, “The employer should adjust the tax for you.” Second, the figuring is not shared on a joint return: “Figure this amount separately for you and your spouse.”
Tier 2 RRTA tax and the refund claim route
If the employer does not correct the excess withholding, the instructions say “you can file a claim for refund using Form 843.” Tier 2 railroad retirement tax is handled differently: “You can’t claim a refund for excess tier 2 RRTA tax on Form 1040, 1040-SR, or 1040-NR.” The next sentence in the instructions is “Instead, use Form 843.”
Where it goes next
Line 11 is one of the amounts added on line 15, which the schedule describes as “Add lines 9 through 12 and 14. Enter here and on Form 1040, 1040-SR, or 1040-NR, line 31”. See the Form 1040 lines 29, 30 and 31 page for the Form 1040 side. The previous line is covered on Schedule 3 line 10 and the next on Schedule 3 line 12.
Edition and line numbers
This page reads the 2025 Schedule 3 (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 3”. 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
- Claiming an excess that came from a single employer. The instructions say “if any one employer withheld more than $10,918.20, you can’t claim the excess on your return.”
- Combining spouses on a joint return. The instructions say “Figure this amount separately for you and your spouse.”
- Using line 11 for tier 2 RRTA tax. The instructions say “You can’t claim a refund for excess tier 2 RRTA tax on Form 1040, 1040-SR, or 1040-NR.”
Related: W-2 box 4 social security tax withheld, Form 1040 lines 29, 30 and 31, Form 1040 line 26, and Form 1040.
Sources
- Instructions for Form 1040 and Form 1040-SR (2025): https://www.irs.gov/pub/irs-pdf/i1040gi.pdf
- Schedule 3 (Form 1040), Additional Credits and Payments (2025): https://www.irs.gov/pub/irs-pdf/f1040s3.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.