U.S. · Tax forms
Form 3800 line 6, add lines 1, 3, 4, and 5.
The Part I total for credits not allowed against tentative minimum tax, and where it goes next.
Line 6 is “Add lines 1, 3, 4, and 5.” It totals the Part I credits: non-passive current credits (line 1), the allowed part of passive credits (line 3), non-passive carryforwards to 2025 (line 4), and carrybacks from 2026 (line 5). Line 17 then takes the smaller of line 6 or line 16.
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Result
What the 2025 Form 3800 says
| Item | Meaning | What the IRS says |
|---|---|---|
| Line 1 | Non-passive current credits | Non-passive credits from Part III, line 2: combine column (e) with non-passive amounts from column (f). Do not take into account any amount in column (f) from passive activities |
| Line 2 | Not added directly | Credits subject to the passive activity limit. It is not in the line 6 sum; only the allowed part, on line 3, is |
| Line 3 | Allowed passive credits | The applicable passive activity credit amount allowed from Form 8582-CR or Form 8810; if no credits are allowed, enter -0-. Do not include specified credits |
| Line 4 | Non-passive carryforwards | Non-passive carryforwards to 2025 of unused credits reported from line 6 of Part IV, column (f); check the box if an amount was changed or revised |
| Line 5 | Carrybacks from 2026 | Use only when you amend your 2025 return to carry back unused credits from 2026; enter the non-passive amount reported from line 6 of Part IV, column (f) |
| Line 6 | Total | Add lines 1, 3, 4 and 5 |
| Line 17 | Limit applied | The form says to enter the smaller of line 6 or line 16 as the credit allowed after the limitation based on the amount of tax |
Why line 2 is not in the total
Line 2 collects credits that are subject to the passive activity limit. Those credits count toward line 6 only to the extent they are allowed, and that allowed amount is entered on line 3 from Form 8582-CR or Form 8810. Adding line 2 itself would count credits that may not be usable this year.
Complete Parts III and IV first
The form says to complete the applicable portions of Parts III and IV before Parts I and II, and the instructions repeat that column entries come first.
What happens after line 6
Part II Section A compares tax with the credit. Line 16 is net income tax less the greater of line 13 or line 14, and line 17 takes the smaller of line 6 or line 16. The instructions note that unused credit is carried back or forward when the tax liability limit is smaller than the sum of the credit lines.
Worked example
Line 1 is $12,000. Line 3 is $0 because no passive credits are allowed. Line 4 is $3,000 of non-passive carryforward. Line 5 is $0. Line 6 is $12,000 plus $0 plus $3,000 plus $0, which is $15,000. If line 16 is $9,000, line 17 is $9,000, the smaller of the two. Names and figures are made up.
More line pages in this set
Related lines: Form 3800 Line 33, Form 3800 Line 10b.
Sources
- Instructions for Form 3800 and Schedule A (2025): the line-by-line instructions on this page. Page last reviewed or updated April 30, 2026. Read November 2, 2026.
- Form 3800, General Business Credit (2025): the printed line wording and arithmetic on the form. Read November 2, 2026.
Tax year 2025 form and instructions. Line labels were read from the IRS PDF posted on the date read; line numbers, dollar limits and cutoff years change between editions, so check them against the form for your tax year. Line numbers on Form 3800 changed in the 2025 edition (for example, Part I line 2 now includes passive carryovers), so check the form for your tax year. Names in worked examples are made up.
Frequently asked questions
What does Form 3800 line 6 add up?
Lines 1, 3, 4 and 5 of Part I.
Why is line 2 not included?
Line 2 is the passive credit total before the passive activity limit; only the allowed part, line 3, is added.
What is the label “Part I”?
Credits not allowed against tentative minimum tax (TMT).
What do I do with line 6?
It is compared to line 16 in Part II, Section A; line 17 is the smaller of the two.
When do I use line 5?
Only when you amend your 2025 return to carry back unused credits from 2026.
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.