Updated October 18, 2026. Quick answer: Line 25b is the part of line 25a that came from qualified disaster distributions from a Roth IRA, and it is zero if you had none. Line 25c is the taxable amount, line 25a less line 25b, adjusted by the 2025 Line 25c Worksheet if you repaid certain distributions. A positive result also goes on Form 1040 line 4b.
Retirement forms read line by line: Form 8915-F lines 16 to 26.
What lines 25b and 25c ask for
The caption for line 25b reads “Enter the amount on line 25a attributable to qualified disaster distributions, if any, from 2025 Form(s) 8915-F.” It adds “Also, enter this amount on 2025 Form(s) 8915-F, line 19, as applicable.”
The caption for line 25c reads “Taxable amount. Subtract line 25b from line 25a. Reduce that amount by certain 2025 retirement plan distribution repayments (other than those reported on Form 8915-F) that are treated as rollovers.” It then says “If more than zero, also include this amount on 2025 Form 1040, 1040-SR, or 1040-NR, line 4b”.
Line 25b: where the number comes from
The instructions give three cases, the same shape as line 15b. The first is “If you have no qualified disaster distributions in 2025 from a Roth IRA, enter -0- on line 25b.” The second is “If all your distributions in 2025 from Roth IRAs are qualified disaster distributions, enter the amount from line 25a on line 25b.”
For a mix, “you will need to multiply the amount on line 25a by a fraction.” The instructions describe it: “The numerator of the fraction is your total qualified” disaster distributions, and “the denominator is the amount from Form 8606, line 21.” Two worked examples are in the instructions. The traditional IRA version of this step is on the lines 15a and 15b page.
The 2025 Line 25c Worksheet
The instructions include a worksheet named the 2025 Line 25c Worksheet: “The 2025 Line 25c Worksheet is for filers who have reported on Form 8606, line 19, certain 2025 retirement plan distribution repayments treated as rollovers, but is not for repayments reported on Form 8915-F.” This page does not reproduce its figures; use the worksheet in the instructions. The instructions say “The amount on line 4 of the worksheet is the taxable income you will enter on line 25c of your 2025 Form 8606.” and “The amount, if any, on line 5 of the worksheet is the amount you will include on line 22 of your Form 8606 in the next year after 2025 you report Roth IRA distributions on Form 8606.”
Timing matters: “If the repayment was made after 2025 and within the 3-year repayment period, you may need to file an amended 2025 return.”
Where it goes next
A positive line 25c goes to Form 1040 line 4b, as the caption says; see Form 1040 lines 4a and 4b. The instructions also warn “If you were under age 591/2 at the time you received distributions from your Roth IRA, there is generally an additional 10% tax on the portion of the distribution that is included in income”. The tax itself is figured on Form 5329. The step before this one is on the lines 24 and 25a page.
Edition and line numbers
This page reads the 2025 Form 8606 and its 2025 instructions, the current files irs.gov served on 2026-10-18. They are the files for the tax year 2025 return, filed in 2026. The form says “Attach to 2025 Form 1040, 1040-SR, or 1040-NR.” 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. The full form is explained on the Form 8606 page.
Common mistakes
- Leaving line 25b blank when there were no disaster distributions. The instructions say “If you have no qualified disaster distributions in 2025 from a Roth IRA, enter -0- on line 25b.”
- Using the line 7 total as the denominator. For Roth IRA distributions the instructions say “the denominator is the amount from Form 8606, line 21.”
- Skipping the worksheet after a repayment. The instructions say it is for filers with “certain 2025 retirement plan distribution repayments treated as rollovers” on line 19.
Related: Form 8606, Form 1040 lines 4a and 4b, Form 5329, and Schedule 2.
Sources
- Instructions for Form 8606, Nondeductible IRAs (2025): https://www.irs.gov/pub/irs-pdf/i8606.pdf
- Form 8606, Nondeductible IRAs (2025): https://www.irs.gov/pub/irs-pdf/f8606.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.