Schedule K-1 (Form 1065), box 13
Box 13: Other deductions
Charitable gifts, investment interest, medical insurance and many other deductions, each with its own code letter.
What box 13 reports
Deductions that do not belong in boxes 1 to 12. Each line is a code letter and an amount, and the box can have several lines.
Many codes are itemized-deduction items, which are only useful to you if you itemize.
Where it goes on your return
Depends on the code
The common case
Each code points to a different form. In 2025, for example, codes A and B (cash contributions) go to Schedule A, line 11; code H (investment interest expense) goes to Form 4952; code K (excess business interest expense) goes to Form 8990.
When it depends on you
Itemizing, basis, at-risk and passive rules can all limit a box 13 item. See the Partner's Instructions for each code.
Common codes in box 13
| Code | Title | Goes to |
|---|---|---|
| A | Cash contributions (60%) | Schedule A, line 11 |
| B | Cash contributions (30%) | Schedule A, line 11 |
| C | Noncash contributions (50%) | Schedule A, line 12 |
| D | Noncash contributions (30%) | Schedule A, line 12 |
| H | Investment interest expense | Form 4952, line 1 |
| I | Deductions - royalty income | Schedule E, line 19 |
| K | Excess business interest expense | Form 8990 |
| L | Deductions - portfolio income (other) | Schedule A, line 16 |
| M | Amounts paid for medical insurance | Schedule 1 (Form 1040), line 17 |
| W | Soil and water conservation (2025 title) | Schedule F, line 12 |
| ZZ | Other | See the attached statement |
Code letters and titles change between tax years: new codes are added and old ones are retired. This list is the 2025 list. K1 FastTax reads and exports only the code letter and the amount, so check the letter against the instructions for the year printed on your K-1 and against the partnership's attached statement.
A real example line
Below, a line written the way the document text arrives, run through the same reader as your upload. The reader matches the box number and the IRS label, then reads the amount, so it still finds the line when the scan is noisy.
| Line as the engine reads it | Box | Recorded value | Status |
|---|---|---|---|
13 Other deductions A 1,200 H 340 L 85 | 13 | A 1,200; H 340; L 85 | Read |
Check before you enter it
- Box 13 is where code drift bites hardest: a letter that meant one deduction in an earlier year can mean another now.
- A statement may break one code line into several items.
In the K1 FastTax output
CSV column: box_13_codes, for example A:1200;H:340;L:85. In the checklist a line looks like Schedule K-1 (1065) screen, box 13, code A. All CSV columns.
Official source
The IRS text for every box is in the Partner’s Instructions for Schedule K-1 (Form 1065). Use the edition for the tax year printed on your K-1, because box wording and code lists change.
Plain answers
Questions about box 13
Where do the codes in box 13 go on my return?
Each code points to a different form. In 2025, for example, codes A and B (cash contributions) go to Schedule A, line 11, code H (investment interest expense) goes to Form 4952, and code K (excess business interest expense) goes to Form 8990. See the Partner's Instructions for each code.
Do I need to itemize to use the deductions in box 13?
Many box 13 codes are itemized-deduction items, such as charitable contributions, and they only help you if you itemize. Others go elsewhere, for example code M (amounts paid for medical insurance) goes to Schedule 1 (Form 1040). Check each code before you decide.
A box 13 code letter does not match last year's K-1. Why?
Code letters and titles change between tax years: new codes are added and old ones are retired. Use the Partner's Instructions for the year printed on your K-1 and the partnership's statement, and do not rely on last year's letter.
Box 13 shows ZZ and STMT. What do I enter?
Code ZZ means other, and STMT means the amount and the details are on a statement attached to the K-1. Read the statement. K1 FastTax records ZZ:STMT in the CSV and adds the line to the review list, but it does not read the statement.
Can box 13 have several lines?
Yes. Each line is a code letter and an amount, and a statement may break one code line into several items. K1 FastTax writes the lines into one box_13_codes cell, for example A:1200;H:340;L:85. The plain box_13 column stays empty for coded boxes.
Can I deduct everything shown in box 13?
Not automatically. Itemizing, basis, at-risk and passive rules can all limit a box 13 item. See the Partner's Instructions for Schedule K-1 (Form 1065) for each code.
Is box 13 the same on a Form 1120-S or Form 1041 K-1?
Other deductions are box 12 on a Form 1120-S K-1 and boxes 9 and 11 on a Form 1041 K-1. The code lists differ between forms, so use the instructions for the form in front of you.
Related boxes
Read box 13 from your own K-1
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