This is the simplest to use, but it's only available if:

• Your filing status is single or married filing jointly;
• You don't claim any dependents;
• You (and your spouse if filing a joint return) were under age 65 and not blind at the end of the tax year;
• Your taxable income is less than $100,000;
• Your income is only from wages, salaries, tips, unemployment compensation, Alaska Permanent Fund dividends, taxable scholarship and fellowship grants, and taxable interest of $1,500 or less;
• You didn't receive any advance earned income credit (EIC) payments;
• You don't claim any adjustments to income, such as a deduction for student loan interest;
• You don't claim any credits other than the EIC; and
• You don't owe any household employment taxes on wages you paid to a household employee.

If you don't qualify to use Form 1040EZ, you may be able to use Form 1040A if:

• Your income is only from wages, salaries, tips, IRA distributions, pensions and annuities, taxable social security and railroad retirement benefits, taxable scholarship and fellowship grants, interest, ordinary dividends (including Alaska Permanent Fund dividends), capital gain distributions, and unemployment compensation;
• Your taxable income is less than $100,000;
• Your adjustments to income are for only the following items:
  (1) Educator expenses
  (2) IRA deduction
  (3) Student loan interest deduction
  (4) Tuition and fees deduction
• You don't itemize your deductions;
• Your taxes are only from the following:
  (1) Tax Table
  (2) Alternative minimum tax
  (3) EIC payments, if you received any
  recapture of an education credit.
  (4) Form 8615, Tax for Children Under Age 14 With Investment Income of More Than $1,600
  (5) Qualified Dividends and Capital GainTax Worksheet
• You claim only the following tax credits
  (1) The credit for child and dependent care expenses.
  (2) The credit for the elderly or the disabled.
  (3) The child tax credit.
  (4) The additional child tax credit.
  (5) The education credits.
  (6) The retirement savings contributions credit.
  (7) The earned income credit.
  (8) The adoption credit.
• You did not have an alternative minimum tax adjustment on stock you acquired from the exercise of an incentive stock option.

If you cannot use Form 1040EZ or Form 1040A, you must use Form 1040 which can include all types of income, deductions, and credits.

It may be to your advantage to file a Form 1040 even if you qualify for a different form because it allows you to take itemized deductions, adjustments to income, and credits. However, you must use Form 1040 if:

• Your taxable income is $100,000 or more;
• You itemize your deductions;
• You had income that cannot be reported on Form 1040EZ or Form 1040A, including tax-exempt interest from private activity bonds issued after August 7, 1986;
• You claim any adjustments to gross income other than the adjustments listed earlier under Form 1040A;
• Your Form W-2, box 12, shows uncollected employee tax (social security and Medicare tax) on tips or group-term life insurance;
• You received $20 or more in tips in any one month and did not report all of them to your employer;
• You claim any credits other than the credits listed earlier under Form 1040A;
• You owe the excise tax on insider stock compensation from an expatriated corporation;
• Your Form W-2 shows an amount in box 12 with a code Z; and
• You have to file other forms with your return to report certain exclusions, taxes, or transactions.