U.S. · Tax forms
Form 8379 line 15, standard deduction or itemized deductions.
How the joint-return deduction is divided between spouses, with the basic amounts and the age and blindness worksheet.
Line 15 of Form 8379 is the standard deduction or itemized deductions. In column (a) enter the amount from Form 1040 or 1040-SR line 12. If you used the standard deduction, columns (b) and (c) each include one-half of the basic standard deduction ($29,200 for 2024 and $30,000 for 2025 per the instructions), plus each spouse’s own age or blindness amount. If you itemized, give each spouse the deductions that belong to them.
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Result
How line 15 is filled in
| Situation | Type | What the IRS says |
|---|---|---|
| Column (a) | Joint return amount | Enter the standard deduction or itemized deductions shown on your joint return, generally reported on Form 1040 or 1040-SR, line 12. |
| Standard deduction, columns (b) and (c) | Split | Include one-half of your basic standard deduction in each column. |
| Basic standard deduction, 2024 | Amount | $29,200, as listed in the instructions table. |
| Basic standard deduction, 2025 | Amount | $30,000, as listed in the instructions table. |
| Additional standard deduction, 2024 | Amount | $1,550 per box checked for age or blindness, as listed in the worksheet. |
| Additional standard deduction, 2025 | Amount | $1,600 per box checked for age or blindness, as listed in the worksheet. |
| Someone can claim you or your spouse as a dependent | Exception | Your basic standard deduction is the amount on line 4c of the Standard Deduction Worksheet for Dependents in the Form 1040 instructions. |
| Itemized deductions, columns (b) and (c) | Allocation | Include each spouse's separate deductions, such as state and local income taxes. Allocate other deductions as you determine. |
What line 15 does
Line 15 is part of Part III of Form 8379, where the joint return is allocated between the injured spouse and the other spouse as if each had filed a separate return. Column (a) matches the joint return. Columns (b) and (c) must add back up to column (a). Line 15 applies to whichever deduction route the couple took: the standard deduction or itemized deductions.
The standard deduction split
If the couple took the standard deduction, each column gets one-half of the basic standard deduction. The instructions list the basic standard deduction as $29,200 for 2024 and $30,000 for 2025, so for 2025 each column starts at $15,000. If someone could claim you or your spouse as a dependent, the basic standard deduction is instead the amount on line 4c of the Standard Deduction Worksheet for Dependents in the Form 1040 instructions.
Age and blindness boxes are handled separately because they belong to a specific person. The worksheet in the instructions counts the boxes checked for the injured spouse on the joint return and multiplies by the additional standard deduction, $1,550 for 2024 and $1,600 for 2025. That amount goes on line 15, column (b). It repeats the count for the other spouse, and that amount goes in column (c).
Made-up example for 2025. The injured spouse checked one age box. Column (a) is the joint standard deduction of $30,000 plus $1,600 = $31,600. Column (b) is $15,000 + $1,600 = $16,600, and column (c) is $15,000. The totals match: $16,600 + $15,000 = $31,600. The figures use the instruction amounts for illustration only.
If you itemized
For itemized deductions the instructions are brief: in columns (b) and (c), include each spouse’s separate deductions, such as state and local income taxes, and allocate other deductions as you determine. The guide to Part III as a whole says to allocate items to the spouse who would have shown them on a separate return, and that a deduction that would not be allowed on a separate return is allocated between the spouses from the joint figure. Student loan interest is the instructions’ example of a deduction generally not allowed on a separate return.
Items that cannot be tied to either spouse, like a penalty on early withdrawal of savings from a joint bank account, are divided equally.
Why the split matters
The injured spouse’s refund is figured from the allocated income, deductions, credits, withholding and payments. A larger deduction in column (b) lowers the injured spouse’s separate taxable income and tax, which can increase the part of the refund that is protected. The IRS applies the allocation to determine the amount of any refund due the injured spouse. If you live in a community property state, the instructions say the IRS applies your state’s community property laws based on your allocation when you checked the “Yes” box on line 5.
More line pages in this set
Related line page: Form 8379 Line 20.
Sources
- Instructions for Form 8379 (Rev. November 2024): the Part III line-by-line instructions on this page. Read November 2, 2026.
- Form 8379 (Rev. November 2023), Injured Spouse Allocation: the printed line wording on page 2. Read November 2, 2026.
Instructions for Form 8379, Rev. November 2024. The line labels were read from the Form 8379 (Rev. November 2023) PDF and the Instructions for Form 8379 (Rev. November 2024) that the IRS had posted on the date read. Line numbers and dollar amounts change by year, so check them against the form for your tax year. Examples marked made-up use invented figures.
Frequently asked questions
What goes in column (a) of Form 8379 line 15?
The standard deduction or itemized deductions shown on your joint return, generally reported on Form 1040 or 1040-SR line 12.
How do I split the standard deduction?
Include one-half of your basic standard deduction in columns (b) and (c). The instructions list the basic amount as $29,200 for 2024 and $30,000 for 2025.
How are age and blindness amounts allocated?
Count the boxes checked for each spouse and multiply by the additional standard deduction ($1,550 for 2024, $1,600 for 2025). Each spouse's amount goes in that spouse's column.
What if we itemized?
Include each spouse's separate deductions, such as state and local income taxes, and allocate other deductions as you determine.
What if someone can claim me or my spouse as a dependent?
Your basic standard deduction is the amount on line 4c of the Standard Deduction Worksheet for Dependents in the Form 1040 instructions.
Not tax advice
This page summarizes IRS instructions, mostly written for the people who prepare the form, and is not tax, legal or financial advice. A CPA or an enrolled agent can confirm what a line means for your return. Everything runs in your browser; nothing you enter is sent anywhere.