How to Recompute the Alternative Minimum Tax

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The Internal Revenue Service (IRS) imposes an income tax on individuals, under the authority of U.S. Code Title 26, Subtitle A, Chapter 1, Subchapter A, Part I, Section 1. To ensure that no deductions or credits offered are overly taken advantage of, the IRS also imposes an alternative minimum tax on individuals, as per U.S. Code Title 26, Subtitle A, Chapter 1, Subchapter A, Part VI, Section 55. The imposition of the alternative minimum tax requires certain individuals to recompute their income tax using an alternate formula, with IRS Form 6251.

Download IRS Form 6251 and IRS Form 6251 Instructions from the IRS website (see Resources). IRS forms can also be requested by mail.

Read the Form 6251 Instructions to determine whether you must fill out and attach Form 6251 to your federal income tax return. The filing requirements are listed on page 1 of the instructions, in the “General Instructions” section.

Adjust your adjusted gross income from your federal tax return, Line 38 of IRS Form 1040, for the following:
medical and dental from Schedule A (Form 1040), taxes from Schedule A, home mortgage interest, miscellaneous deductions from Schedule A, tax refund from Form 1040, investment interest expense, depletion, net operating loss deduction from Form 1040, alternative tax net operating loss deduction, interest from specified private activity bonds, qualified small business stock, incentive stock options, estates and trusts, electing large partnerships, disposition of property, depreciation on certain assets, passive activities, loss limitations, circulation costs, long-term contracts, mining costs, research and experimental costs, income from certain installment sales, intangible drilling costs and other adjustments, including income-based related adjustments. Record the adjustments on the appropriate lines of Form 6251, Lines 1-27. This is your alternative minimum taxable income.

Subtract from alternative minimum taxable income the following (Form 6251, Lines 29 to 32): exemption from alternative minimum tax, as described on Line 29; the amount from the Foreign Earned Income Tax Worksheet on page 9 of the Form 6251 Instructions and the alternative minimum tax foreign tax credit, if applicable. Enter the amount on Form 6251, Line 33. This is your tentative minimum tax.

Subtract income tax from Form 1040, line 44 (less tax from Form 4972 and foreign tax credits from Form 1040, line 47) from your tentative minimum tax. Enter the amount on Form 3651, Line 35. This is your alternative minimum tax.


  • IRS Form 6251 may require additional steps, beyond calculation of the alternative minimum tax, before being filed. Read the instructions for Part III of the form to determine whether you must continue beyond recomputing your alternative minimum tax.