Updated October 17, 2026. Quick answer: Line 22 of Form 1040 subtracts line 21 from line 18, line 23 carries other taxes, including self-employment tax, from Schedule 2, line 21, and line 24 adds lines 22 and 23. Line 24 is the form’s total tax, and it is the figure your payments are compared with.
More IRS forms and schedules for individual filers, read line by line: Schedule H instructions, Schedule H Part I and Schedule H Part II FUTA tax.
Form lines read one part at a time: Form 8959 Part I and Form 8959 Parts IV and V.
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 18 to 23 and Form 1040-X Parts II and III.
Schedule C and Schedule SE (Form 1040) for 2025, read line by line: Schedule SE lines 5 to 13.
Form 8962 (premium tax credit) for 2025, read line by line: Form 8962 line 29.
Schedule 3 (Form 1040) for 2025, read line by line: Schedule 3 lines 5a and 5b.
Schedule 2 (Form 1040) for 2025, read line by line: Schedule 2 line 9, Schedule 2 lines 17a and 17b and Schedule 2 lines 17z and 18.
What lines 22 to 24 ask for
The form’s caption for line 22 reads “Subtract line 21 from line 18.” The caption for line 23 reads “Other taxes, including self-employment tax, from Schedule 2, line 21”. The caption for line 24 reads “Add lines 22 and 23. This is your total tax”. Three steps, then: a subtraction, a transfer, and an addition.
The credits that line 22 subtracts are covered in lines 19 to 21, and the amount they are subtracted from is built in lines 17 and 18. The whole form is mapped in Form 1040 line by line.
Line 22: subtracting the credits
Line 22 takes the line 18 figure and removes the line 21 credit total. The caption continues with a rule for what to do if nothing is left: “Subtract line 21 from line 18. If zero or less, enter” the zero entry the form shows. In other words, the credits on this line cannot push line 22 below zero. That matters because it keeps a credit total from turning the tax into a negative figure on this line, and it means line 22 is always a figure you can carry into the addition on line 24.
A labelled illustration, not an IRS example, computed from made up numbers: if line 18 is $10,200 and line 21 is $2,350 then line 22 is computed as $10,200 minus $2,350 which is $7,850. If line 21 were larger than line 18, line 22 would show the zero entry instead of a negative figure.
Line 23: other taxes from Schedule 2
Line 23 is a transfer from Schedule 2, and it stays a transfer. The instructions for Schedule 2 say “Enter the amount on Schedule 2, line 21, on Form 1040 or 1040-SR, line 23”. Schedule 2 is explained on its own page, and the form’s caption names one item included on the line, self-employment tax, which is discussed on the self-employment tax page. Everything else on line 23 comes from the schedule, and this page does not restate its contents.
Line 24: your total tax
Line 24 follows its caption: add line 22 and line 23. Continuing the made up illustration, not an IRS example: if line 22 is $7,850 and line 23 is $900 then line 24 is $7,850 plus $900 which is $8,750.
The form labels this figure for you with the words “This is your total tax”. Credits for withholding and payments do not reduce line 24. They are counted on the payments side of the form and compared with it.
Where it goes next
Line 24 is the figure your payments are measured against. The form’s caption for line 33 reads “Add lines 25d, 26, and 32. These are your total payments”. The refund line then reads “If line 33 is more than line 24, subtract line 24 from line 33. This is the amount you overpaid”, and the amount owed line begins “Subtract line 33 from line 24. This is the amount you owe.” The payments that go into line 33 begin with line 25.
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
- Subtracting the credits from the wrong starting figure. The form’s caption is “Subtract line 21 from line 18.”
- Entering a negative number on line 22 when credits exceed the tax. The caption’s zero-or-less rule is “Subtract line 21 from line 18. If zero or less, enter” followed by the zero entry.
- Forgetting that line 23 comes from Schedule 2. The instructions say “Enter the amount on Schedule 2, line 21, on Form 1040 or 1040-SR, line 23”
Related: Schedule 2 (Form 1040), Self-employment tax explained, 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.