Updated October 18, 2026. Quick answer: Line 2l is where you enter the difference between your regular tax depreciation and your AMT depreciation on assets placed in service after 1986. The form prints the caption, and the instructions say which property must be refigured and which must not. You get the number by refiguring the depreciation for the AMT and subtracting it from the regular tax deduction.
What line 2l asks for
The caption on the form reads “Depreciation on assets placed in service after 1986 (difference between regular tax and AMT)”. The instructions open the topic by saying “This section describes when depreciation must be refigured for the AMT and how to figure the amount to enter on line 2l.” This page is part of the Form 6251 line-by-line series, and the lines just before this one are on the line 2k page.
Depreciation that does not belong on line 2l
“Don’t use line 2l for depreciation related to the following.” The instructions then list four cases and send each one to its own line. For passive activities: “Passive activities. Take this adjustment into account on line 2m.” For an activity where you are not at risk: “An activity for which you aren’t at risk. Take this adjustment into account on line 2n.” For a partnership or S corporation: “Income or loss from a partnership or an S corporation if the basis limitations apply. Take this adjustment into account on line 2n.” And for a farm shelter: “A tax shelter farm activity. Take this adjustment into account on line 3.” Lines 2m and 2n are on the lines 2m to 2t page, and line 3 is on the lines 3 and 4 page.
“To avoid duplication, any AMT adjustment or tax preference item taken into account on this line shouldn’t be taken into account in figuring the amount to enter on any other adjustment or tax preference item line of this form.”
Which property must be refigured
The instructions say “Generally, you must refigure depreciation for the AMT, including depreciation allocable to inventory costs, for:” and list three groups. The first is “Property placed in service after 1998 that is depreciated for the regular tax using the 200% declining balance method”. The third is “Tangible property placed in service after 1986 and before 1999.” For the full list, including the middle group of section 1250 property, read the instructions for line 2l itself.
Which property is left alone
“Don’t refigure depreciation for the AMT for the following.” The list includes “Residential rental property placed in service after 1998.” It also includes “Any part of the cost of any property for which you elected to take a section 179 expense deduction.” and “Motion picture films, videotapes, or sound recordings.” If a piece of property is on this list, it adds nothing to line 2l. Regular-tax depreciation for property in general is explained on the Form 4562 page.
Where the number comes from
For older property the instructions say “Refigure depreciation for the AMT using ADS, with the same convention used for the regular tax.” For newer property: “Use the same convention and recovery period used for the regular tax.” “For property other than section 1250 property, use the 150% declining balance method, switching to straight line the first tax year it gives a larger deduction.” “For section 1250 property, use the straight line method.”
The class life question is answered in the instructions: “See Pub. 946 for tables that can be used to figure AMT depreciation.” The method-and-recovery-period table for older property is printed in the instructions under the heading for how depreciation is refigured, and this page does not copy it.
Then you take the difference. “Subtract the AMT deduction for depreciation from the regular tax deduction and enter the result.” “If the AMT deduction is more than the regular tax deduction, enter the difference as a negative amount.” Capitalized depreciation counts too: “also adjust the amount of depreciation that was capitalized, if any, to account for the difference between the rules for the regular tax and the AMT.”
Where it goes next
Line 2l is one of the amounts combined on line 4. The form’s line 4 caption says “Alternative minimum taxable income. Combine lines 1b through 3.” The line 4 total is explained on the lines 3 and 4 page, and the AMT it feeds is on the Schedule 2 lines 2 and 3 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 passive activity depreciation on line 2l. The instructions say “Passive activities. Take this adjustment into account on line 2m.”
- Refiguring a section 179 amount. The instructions say “Any part of the cost of any property for which you elected to take a section 179 expense deduction.” is on the list of property where you do not refigure depreciation.
- Entering a positive number when the AMT deduction is larger. 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 4562, depreciation recapture, Schedule 2 lines 2 and 3, and Form 8582.
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.