Updated October 18, 2026. Quick answer: Lines 2m to 2t each take one AMT difference: passive activities, loss limitations, circulation costs, long-term contracts, mining costs, research costs, one installment sale line and intangible drilling costs. The captions on the form say how to read each difference, and most lines take the regular tax figure against the AMT figure. The instructions give a short paragraph for each line.
The eight lines at a glance
These are the captions printed on the form for each line. They come right after line 2l and before the lines 3 and 4 lines.
| Line | Caption on the form |
|---|---|
| 2m | “Passive activities (difference between AMT and regular tax income or loss)” |
| 2n | “Loss limitations (difference between AMT and regular tax income or loss)” |
| 2o | “Circulation costs (difference between regular tax and AMT)” |
| 2p | “Long-term contracts (difference between AMT and regular tax income)” |
| 2q | “Mining costs (difference between regular tax and AMT)” |
| 2r | “Research and experimental costs (difference between regular tax and AMT)” |
| 2s | “Income from certain installment sales before January 1, 1987” |
| 2t | “Intangible drilling costs preference” |
Line 2m: passive activities
“Refigure your passive activity gains and losses for the AMT by taking into account all adjustments and preferences and any AMT prior year unallowed losses that apply to that activity.” The instructions let you work it out on the side: “You may fill out an AMT Form 8582, Passive Activity Loss Limitations, and AMT versions of the other forms or schedules on which your passive activities are reported, to determine your passive activity loss allowed for the AMT”. Then “don’t file the AMT versions of these forms and schedules with your tax return. Instead, keep them with your records.” The regular passive loss form is covered on the Form 8582 page.
“Enter the difference between the amount that would be reported for the activity on Schedule C, E, or F or Form 4835, Farm Rental Income and Expenses, for the AMT and the regular tax amount.” “If (a) the AMT loss is more than the regular tax loss, (b) the AMT gain is less than the regular tax gain, or (c) you have an AMT loss and a regular tax gain, enter the adjustment as a negative amount.”
One carve-out: “Enter any adjustment for amounts reported on Form 8949, Schedule D, Form 4684, or Form 4797, for the activity on line 2k instead of line 2m.” That is the line 2k page. A publicly traded partnership has its own paragraph: “If you had a loss from a PTP, refigure the loss using any AMT adjustments and preferences and any AMT prior year unallowed loss.”
Line 2n: loss limitations
“Refigure your gains and losses from activities for which you aren’t at risk” and the basis limits for partnerships and S corporations, taking the AMT adjustments into account. “For passive activities, see the line 2m instructions instead.”
“Enter the difference between the amount that would be reported for the activity on Schedule C, E, or F or Form 4835 for the AMT and the regular tax amount.” “Enter any adjustment for amounts reported on Form 8949, Schedule D, Form 4684, or Form 4797 for the activity on line 2k instead of line 2n.”
Lines 2o, 2q and 2r: costs spread over years for the AMT
Circulation costs: “Circulation costs (expenditures to establish, maintain, or increase the circulation of a newspaper, magazine, or other periodical) deducted in full for the regular tax in the year they were paid or incurred must be capitalized and amortized over 3 years for the AMT.” “Enter the difference between the regular tax and AMT deduction.”
Mining costs: “Mining exploration and development costs deducted in full for the regular tax in the tax year they were paid or incurred must be capitalized and amortized over 10 years for the AMT.” “If the AMT deduction is more than the regular tax deduction, enter the difference as a negative amount.”
Research and experimental costs: “Research and experimental costs deducted under section 174(a) or section 174A(a) for regular tax purposes generally must be amortized for AMT purposes over 10 years beginning with the year the costs were paid or incurred.” “Enter the difference between the amount allowed for AMT purposes and the amount allowed for regular tax purposes.”
Mining costs carry a warning at the top of the paragraph: “Don’t make this adjustment for costs for which you elected the optional 10-year write-off for the regular tax.” The circulation and research paragraphs open with similar warnings, so read the opening of the paragraph for the line you are on.
Line 2p: long-term contracts
“For the AMT, you must generally use the percentage-of-completion method described in section 460(b) to determine your income from any long-term contract (defined in section 460(f)).” “However, this rule doesn’t apply to any home construction contract (as defined in section 460(e)(5)).” “Enter the difference between the AMT and regular tax income. If the AMT income is smaller, enter the difference as a negative amount.”
Lines 2s and 2t
Line 2s is printed on the form as “Income from certain installment sales before January 1, 1987”. For the instructions that go with it, read the line 2s paragraph in the Instructions for Form 6251.
Line 2t: “IDCs from oil, gas, and geothermal wells are a preference to the extent that the excess IDCs are more than 65% of the net income from the wells.” “Figure the preference for all oil and gas properties separately from the preference for all geothermal properties.” The instructions give the first step for excess IDCs: “Determine the amount of your IDCs allowed for the regular tax under section 263(c), but don’t include any section 263(c) deduction for nonproductive wells.” They also carry an exception paragraph that begins “The preference for IDCs from oil and gas wells doesn’t apply to taxpayers who are independent producers”, followed by “However, this benefit may be limited.” Follow that paragraph’s steps if you are an independent producer.
Where the number comes from
Each line’s number comes from refiguring one item for the AMT and comparing it with what you reported for the regular tax. The instructions repeat a sign rule on several of these lines, so check the paragraph for the line you are on. Keep both sets of figures, because the instructions for line 2m also say “keep adequate records for both the AMT and regular tax.”
Where it goes next
These eight lines are combined with the rest of Part I on line 4. The form says “Alternative minimum taxable income. Combine lines 1b through 3.” The line 4 total is on the lines 3 and 4 page.
Edition and line numbers
This page reads the 2025 Form 6251 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’s own header says “Attach to 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
- Putting a gain or loss from a sale of property on line 2m or 2n. The instructions send it elsewhere: “Enter any adjustment for amounts reported on Form 8949, Schedule D, Form 4684, or Form 4797, for the activity on line 2k instead of line 2m.”
- Filing the side forms with the return. The instructions say “don’t file the AMT versions of these forms and schedules with your tax return.”
- Dropping the minus sign. The instructions say “If the AMT deduction is more than the regular tax deduction, enter the difference as a negative amount.”
Related: Form 6251, Form 8582, Form 8949, Form 4797, and Schedule 2.
Sources
- Instructions for Form 6251, Alternative Minimum Tax, Individuals (2025): https://www.irs.gov/pub/irs-pdf/i6251.pdf
- Form 6251, Alternative Minimum Tax, Individuals (2025): https://www.irs.gov/pub/irs-pdf/f6251.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.