U.S. · Tax forms
Form 6251 line 2l: post-1986 depreciation.
Which assets need AMT depreciation, which do not, and how to figure the adjustment.
Line 2l is the AMT adjustment for post-1986 depreciation: the regular tax depreciation deduction minus the AMT deduction, entered as negative if the AMT deduction is larger. You generally refigure for property placed in service after 1998 depreciated for regular tax with 200% declining balance, section 1250 property not on straight line, and tangible property placed in service after 1986 and before 1999. Depletion is not on this line: it is line 2d.
Look up an AMT depreciation rule
Result
Line 2l rules and the depletion line
| Item | Meaning | Where it goes (per the IRS instructions) |
|---|---|---|
| Refigure | Property you must refigure | Property placed in service after 1998 depreciated with 200% declining balance (generally 3-, 5-, 7- and 10-year MACRS), section 1250 property after 1998 not on straight line, and tangible property placed in service after 1986 and before 1999. |
| Skip | Property you do not refigure | Residential rental property after 1998; other section 1250 property after 1998 on straight line; non-1250 property after 1998 on 150% declining balance or straight line; ADS property; section 179 amounts; qualified property whose basis is the same for AMT and regular tax; films, videotapes and sound recordings; unit-of-production property; natural gas gathering lines placed in service after April 11, 2005. |
| Pre-1999 | Method for property before 1999 | ADS with the same convention. Section 1250 property: straight line over 40 years. Other straight line property: straight line over AMT class life. Other tangible property: 150% declining balance, switching to straight line, over AMT class life. |
| Post-1998 | Method for property after 1998 | Same convention and recovery period as regular tax. Non-1250 property: 150% declining balance, switching to straight line. Section 1250 property: straight line. |
| 12 years | Default class life | Use 12 years for any tangible personal property not assigned an AMT class life. |
| 2d | Depletion (not line 2l) | Refigure depletion for the AMT using only AMT income and deductions. Enter the difference between regular and AMT deductions; negative if AMT is more. |
Correction to the research row. The research row paired line 2l with depletion. In the 2025 instructions, line 2l is post-1986 depreciation and depletion is line 2d, so this page covers line 2l and shows 2d in the table. The page address says post-1986 depreciation.
Do not double count
To avoid duplication, an AMT adjustment or preference taken into account on line 2l should not be taken into account on any other adjustment line. Do not use line 2l for depreciation related to passive activities (line 2m), activities where you are not at risk or partnership and S corporation basis limits (line 2n), or a tax shelter farm activity (line 3).
How to figure the adjustment
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. Also adjust any depreciation that was capitalized, and include the current-year effect on this line. See Pub. 946 for AMT depreciation tables.
Worked example
Omar placed 5-year equipment in service in 2022 and takes $9,600 of regular tax depreciation in 2025 using 200% declining balance. Suppose the AMT deduction, refigured as the instructions require, is $7,200. Line 2l is $9,600 minus $7,200, or a $2,400 positive adjustment. If a property’s AMT deduction had been larger, the result would be negative.
Special depreciation allowance
If qualified property eligible for a special depreciation allowance has the same depreciable basis for AMT and regular tax, no adjustment is required on the remaining basis. If you elected not to take the allowance, the property may be subject to an AMT adjustment.
More IRS form line pages
Other pages in this set: Form 8949 Boxes A-L, Form 5329 Part III, Form 4562 Line 14, Form 4562 Line 12, Form 4562 Convention Codes, Form 5329 Line 52, Form 4562 Line 19, Form 4562 Line 42, Form 6251 Line 2i, Form 6251 Line 2c. The 1099-R box 7 lookup and W-2 box 12 lookup cover the same kind of question for those forms.
Sources
- Instructions for Form 6251 (2025): the sections for the lines and boxes on this page. Read November 2, 2026.
IRS page last reviewed April 30, 2026. Tax year 2025 edition. Line numbers, dollar limits and dates are those printed in the 2025 instructions and can change. Names in worked examples are made up.
Frequently asked questions
Is depletion on line 2l of Form 6251?
No. Line 2l is post-1986 depreciation. Depletion is line 2d.
What property needs AMT depreciation?
Generally property placed in service after 1998 depreciated with 200% declining balance, section 1250 property after 1998 not on straight line, and tangible property placed in service after 1986 and before 1999.
What method is used for AMT depreciation of post-1998 property?
The same convention and recovery period as regular tax, with 150% declining balance switching to straight line for property other than section 1250 property, and straight line for section 1250 property.
What class life do I use if none is assigned?
Use 12 years for tangible personal property not assigned an AMT class life.
How do I figure the line 2l amount?
Subtract the AMT depreciation deduction from the regular tax deduction. If the AMT deduction is more, enter the difference as a negative amount.
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. The payer, a CPA or an enrolled agent can confirm what a box or code means for your return. Everything runs in your browser; nothing you enter is sent anywhere.