Filing Status and Age
You're eligible to file the simple tax return if your filing status is single or married filing jointly. You (and your spouse if filing jointly) must be under the age of 65 and not blind on the last day of the tax year. If you use a different filing status, such as head of household or married filing separately, you must use a different 1040 form, even if you meet the other eligibility requirements.
Dependents and Adjustments
If you have dependent children or qualifying relatives, you must use another 1040 form. You may only use the 1040EZ form if you do not claim an exemption for dependents or have any other adjustments to income. Examples of income adjustments include deductions for student loan interest, tuition and fees, moving expenses and alimony payments.
You can file the simple Form 1040EZ if your income (or the combined income of you and your spouse) is less than $100,000. The source of your income is limited to wages, tips, unemployment, Alaskan Permanent Fund Dividends and taxable scholarships. Your investment income must be less than $1,500 and you can't have income and expenses from self-employment. If you receive a 1099-MISC income form, you must file a regular 1040 tax return.
If you're otherwise eligible to file Form 1040EZ, the only credit you can claim is the earned income credit and federal income tax withholding. Occasionally, a special credit is offered to every taxpayer and 1040EZ filers can claim the credit on the simple form.