Use Form 6251 to figure the amount, if any, of your alternative minimum tax (AMT). The AMT applies to taxpayers who have certain types of income that receive favorable treatment, or who qualify for certain deductions, under the tax law.
These tax benefits can significantly reduce the regular tax of some taxpayers with higher economic incomes. The AMT sets a limit on the amount these benefits can be used to reduce total tax.

Who must file?

Attach Form 6251 to your return if any of the following statements are true.

Form 6251, line 7, is greater than line 10.
You claim any general business credit, and either line 6 (in Part I) of Form 3800 or line 25 of Form 3800 is more than zero.
You claim the qualified electric vehicle credit (Form 8834), the personal use part of the alternative fuel vehicle refueling property credit (Form 8911), or the credit for prior year minimum tax (Form 8801).
The total of Form 6251, lines 2c through 3, is negative and line 7 would be greater than line 10 if you didn’t take into account lines 2c through 3.