Updated October 18, 2026. Quick answer: Line 8 is the net amount you converted from traditional IRAs to Roth IRAs in 2025. The instructions for the line are one sentence long. The same number is also entered on line 16 in Part II.
What line 8 asks for
The form’s caption reads “Enter the net amount you converted from traditional IRAs to Roth IRAs in 2025.” The instructions say: “If, in 2025, you converted any amounts from traditional IRAs to a Roth IRA, enter on line 8 the net amount you converted.” Part I is used for conversions when “You converted part, but not all, of your traditional IRAs to Roth IRAs in 2025 and you made nondeductible contributions to a traditional IRA in 2025 or an earlier year.”
Where the number comes from
The related reporting forms are explained elsewhere on the site. The 1099-R side is on the Form 1099-R box 1 page, and the Form 5498 side on the Form 5498 boxes 2, 3 and 4 page. Conversion amounts are also kept off line 7, as the line 7 page explains. For the planning side, see the Roth conversions page.
Where it goes next
The caption adds a second step: “Also, enter this amount on line 16”. Line 8 is also added into line 9: “Add lines 6, 7, and 8”. Line 11 then reads “Multiply line 8 by line 10.” and the form calls that “the nontaxable portion of the amount you converted to Roth IRAs.” See the lines 9 to 14 page and the lines 16, 17 and 18 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.
Common mistakes
- Forgetting to copy line 8 to line 16. The caption says “Also, enter this amount on line 16”
- Entering a gross figure that the form does not call for. The caption asks for “the net amount you converted from traditional IRAs to Roth IRAs in 2025.”
- Also listing the conversion as a distribution on line 7. The instructions say not to include “Distributions that you converted to a Roth IRA.”
Related: Form 8606, Roth conversions, Roth conversion taxes, Form 5498 boxes 2, 3 and 4, and Form 1099-R box 1.
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.