Updated October 18, 2026. Quick answer: Line 20 is a yes or no question, not a number. If lines 18 and 19 are both zero or blank and you are not filing Form 4952, answer Yes and use the Qualified Dividends and Capital Gain Tax Worksheet. Otherwise answer No and use the Schedule D Tax Worksheet. Either way, skip lines 21 and 22.
Read box by box from the IRS form text: Form 2439 box 2.
What line 20 asks
The question on the form is “Are lines 18 and 19 both zero or blank and you are not filing Form 4952?” It is reached only after a Yes on line 17 (see the lines 16 and 17 page), and it follows the worksheets covered on the line 18 and line 19 pages.
If the answer is Yes
“Yes. Complete the Qualified Dividends and Capital Gain Tax Worksheet in the instructions for Form 1040, line 16.” “Don’t complete lines 21 and 22 below.” The Qualified Dividends and Capital Gain Tax Worksheet page covers that worksheet, and the Form 1040 line 16 page shows where its result lands.
If the answer is No
“No. Complete the Schedule D Tax Worksheet in the instructions.” “Don’t complete lines 21 and 22 below.”
The Schedule D Tax Worksheet has its own scope note: “Complete this worksheet only if line 18 or line 19 of Schedule D is more than zero and lines 15 and 16 of Schedule D are gains or if you file Form 4952 and you have an amount on line 4g, even if you don’t need to file Schedule D.” Form 4952 is the investment interest form, and the Form 4952 page covers it.
When neither worksheet is used
The worksheet page warns about a third case. “Don’t use the Qualified Dividends and Capital Gain Tax Worksheet or this worksheet to figure your tax if:” “Line 15 or line 16 of Schedule D is zero or less and you have no qualified dividends on Form 1040, 1040-SR, or 1040-NR,” or Form 1040 line 15 is zero or less. “Instead, see the instructions for Form 1040, line 16”.
Where the number comes from
There is no amount to enter on line 20. The answer depends on the amounts you already entered on lines 18 and 19 and on whether you file Form 4952. The worksheet itself is a page in the Schedule D instructions: it opens with the instruction “Before completing this worksheet, complete Form 1040, 1040-SR, or 1040-NR through line 15.” This page does not reproduce its line math; follow the printed worksheet.
Where it goes next
Whichever worksheet you use produces your tax for Form 1040. The Schedule D Tax Worksheet ends with “Also, include this amount on Form 1040, 1040-SR, or 1040-NR, line 16.” See the Schedule D (Form 1040) page for the full form.
Edition and line numbers
This page reads the 2025 Schedule D (Form 1040) and its 2025 instructions, the current files irs.gov served on 2026-10-18 (byte-identical to the archived copies). 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.” 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
- Answering Yes while still filing Form 4952. The question requires that you “are not filing Form 4952?” as well as zero or blank lines 18 and 19.
- Filling in lines 21 and 22 after answering line 20. Both answers say “Don’t complete lines 21 and 22 below.”
- Using either worksheet when your line 15 or 16 is a loss or zero with no qualified dividends. The worksheet page says “Don’t use the Qualified Dividends and Capital Gain Tax Worksheet or this worksheet to figure your tax if:”
Related: Schedule D (Form 1040), Qualified Dividends and Capital Gain Tax Worksheet page, Form 1040 line 16 page, and Form 4952 page.
Sources
- Instructions for Schedule D (Form 1040), Capital Gains and Losses (2025): https://www.irs.gov/pub/irs-pdf/i1040sd.pdf
- Schedule D (Form 1040), Capital Gains and Losses (2025): https://www.irs.gov/pub/irs-pdf/f1040sd.pdf
Read from the IRS documents linked above on October 18, 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.