Form 6251, Alternative Minimum Tax - Individuals, and Form 8801, Credit for Prior Year Minimum Tax - Individuals, Estates and Trusts, are the two primary forms used for the AMT. Click on the following links to go the forms and their Instructions.
Form 6251 is used to calculate a taxpayer's AMT liability. The form is broken down into three parts. In Part I, Alternative Minimum Taxable Income, the taxpayer calculates his alternative minimum taxable income, which is used in Part II.
In Part II, Alternative Minimum Tax, the taxpayer determines the amount of his or her AMT liability.
Part III, Tax Computation Using Maximum Capital Gains Rates, is used by a taxpayer that has capital gains income or qualified dividend income to determine the amount of tax to be entered on line 31 in the calculation of his or her AMT liability in Part II.
Form 8801 is used to calculate a taxpayer's refundable (in applicable years only) and nonrefundable (for all years) Minimum Tax Credit (MTC) and MTC carryforward to the next year. In Part I, Net Minimum Tax on Exclusion Items, the taxpayer calculates the amount of his AMT liability from the previous year that was due to AMT permanent exclusion items.
In Part II, Maximum Tax Credit and Carryforward, the taxpayer uses information from the other parts of the form to calculate his or her refundable credits and to determine the amount of any MTC carryforward.
In Part III, Tax Computations Using Maximum Capital Gains Rates, a taxpayer who had capital gains in the previous year calculates the amount of tax to be entered on line 11 in the calculation of the amount of the previous year AMT liability that was due to exclusion items in Part I.