AMT is calculated on Form 6251.
Gains and losses from passive activities must be recalculated using the AMT rules. This is done on a separate Form 8582 (Passive Activity Loss Limitations). The difference between the amount allowed for regular tax and AMT purposes goes on line 18.
Note: The instructions to Form 6251 state that the AMT Form 8582 is not to be filed.
https://www.wkblaw.com/wp-content/uploads/Alternative-Minimum-Tax-of-Individuals-table.pdf
