Updated October 17, 2026. Quick answer: Line 19 of Form 1040 is for the child tax credit or credit for other dependents, taken from Schedule 8812. Line 20 takes the amount from Schedule 3, line 8, and line 21 adds lines 19 and 20. The numbers are copied from those schedules, and line 21 is the credit total that line 22 subtracts.
IRS worksheets read line by line: Schedule 8812 Credit Limit Worksheet A, Form 2441 Credit Limit Worksheet and Form 8880 Credit Limit Worksheet.
More IRS forms and schedules for individual filers, read line by line: Schedule R instructions, Schedule R Part III credit calculation and Form 8839 Part II adoption credit.
Related reading on this site: IRS Notice CP09 (Earned Income Credit worksheet) and IRS Notice CP27 (Earned Income Credit worksheet).
Business use of your home (Form 8829), the saver’s credit (Form 8880), clean vehicle credits (Form 8936) and amended returns (Form 1040-X), read line by line: Form 1040-X lines 6 to 11, Form 1040-X lines 24 to 30 and Form 1040-X Parts II and III.
Foreign tax credit (Form 1116) and alternative minimum tax (Form 6251) for 2025, read line by line: Form 1116 line 8, Form 1116 lines 20 to 24 and Form 1116 line 35.
Schedule 8812 (child tax credit and additional child tax credit) for 2025, read line by line: Schedule 8812, Schedule 8812 lines 15 to 20 and Schedule 8812 line 27.
Line-by-line IRS form guides for 2025: Form 2441 line 8, Form 2441 lines 22 to 31 and Form 8863 lines 9 to 19.
Schedule 3 (Form 1040) for 2025, read line by line: Schedule 3 line 3, Schedule 3 lines 5a and 5b and Schedule 3 lines 6f to 6k.
What lines 19 to 21 ask for
The form’s caption for line 19 reads “Child tax credit or credit for other dependents from Schedule 8812”. The caption for line 20 reads “Amount from Schedule 3, line 8”, and the caption for line 21 reads “Add lines 19 and 20”. Lines 19 and 20 each carry a number over from another schedule, and line 21 adds the two.
The lines before these are covered in lines 17 and 18, and the full walk through the form is in Form 1040 line by line.
Line 19: child tax credit and credit for other dependents
The instructions for line 19 point you to the schedule that does the figuring: “See Schedule 8812 and its instructions for information on figuring and claiming any child tax credit and credit for other dependents that you may qualify to claim.” So the amount entered on line 19 is the result from Schedule 8812, not something worked out on the face of Form 1040. For background on the credit itself, see the child tax credit page.
The instructions also set a Social Security number condition for the child tax credit: “To claim the child tax credit, you must have a valid SSN”. They add that the number “must be valid for employment and issued before the due date of your return (including extensions).” Read the full paragraph in the instructions for the joint return and credit for other dependents details before you enter an amount.
Line 20: the Schedule 3 amount
Line 20 is another transfer. The instructions for Schedule 3 say when the schedule is used: “Use Schedule 3 if you have nonrefundable credits, other than the child tax credit or the credit for other dependents”. That is why line 20 sits next to line 19 and not inside it: the child tax credit comes from Schedule 8812 and the other credits come from Schedule 3. The instructions then say where the total goes: “Include the amount on Schedule 3, line 8, in the amount entered on Form 1040, 1040-SR, or 1040-NR, line 20.”
The related payments and refundable credits on Schedule 3 have a separate landing spot further down the form and are not part of line 20. Keep the two schedules straight when you work down the page: Schedule 8812 supplies line 19, Schedule 3 supplies line 20, and Form 1040 itself only adds them. If you have no Schedule 3 amount, there is nothing to carry, and line 21 then rests on line 19 alone. Finish both schedules before you fill in the lines, so that the figures you copy are final.
Line 21: adding the two
Line 21 follows its caption: add line 19 and line 20. A labelled illustration, not an IRS example, with made up numbers: if line 19 is $2,000 and line 20 is $350 then line 21 is $2,000 plus $350 which is $2,350. If one of the two lines has no amount, line 21 equals the other one.
Where it goes next
Line 21 is subtracted from line 18. The form’s caption for line 22 reads “Subtract line 21 from line 18.” So every dollar of credit on lines 19 and 20 lowers the figure that line 22 reports, and the next steps are explained in lines 22 to 24.
Edition and line numbers
This page reads the 2025 Form 1040 and its 2025 instructions, the current files irs.gov served on 2026-10-17. They are the forms for the tax year 2025 return, filed in 2026. The instructions say “The lines on Forms 1040 and 1040-SR are the same.” so everything here applies to Form 1040 and to Form 1040-SR alike. Check the tax year printed on the form you are filling in and use the line numbers on that year’s form, because a different year’s form can number or word its lines differently.
Common mistakes
- Entering a child tax credit figure that did not come from the schedule. The instructions say “See Schedule 8812 and its instructions for information on figuring and claiming any child tax credit and credit for other dependents that you may qualify to claim.”
- Putting the Schedule 3 amount on the wrong line. The instructions say “Include the amount on Schedule 3, line 8, in the amount entered on Form 1040, 1040-SR, or 1040-NR, line 20.”
- Leaving out the Form 8862 requirement when it applies. The instructions say “You must file Form 8862 to claim the child tax credit or credit for other dependents if your child tax credit” and then describe the situations that trigger it.
Related: Child tax credit, Schedule 1 (Form 1040), 2025 tax brackets, and Form 1040.
Sources
- Instructions for Form 1040 and Form 1040-SR (2025): https://www.irs.gov/pub/irs-pdf/i1040gi.pdf
- Form 1040, U.S. Individual Income Tax Return (2025): https://www.irs.gov/pub/irs-pdf/f1040.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.