If you qualify and if you so choose, the IRS will figure your tax and certain credits on Form 1040EZ (PDF), Form 1040A (PDF), or Form 1040 (PDF) if you mail your return by the due date. This applies even if you do not have to file a return, but are filing to claim the earned income credit or a refund of taxes paid. If you paid too much tax (either through withholding or estimated taxes), you will receive a refund. If you did not pay enough, you will receive a bill. If the IRS figures your tax, you will not be charged interest or penalty for late payment if the bill for the tax due is paid within 30 days of the date of the bill, or the due date of the return, whichever is later. If a balance is due, make your check payable to the United States Treasury; be sure to list your social security number(s), tax year, form number, and telephone number on the check or money order. If you did not pay enough tax during the year, you may be charged a penalty for underpayment of estimated tax. Refer to Topic 306, Penalty for Underpayment of Estimated Tax, for more detailed information.

Certain parts of the return will need to be completed and any schedules that apply. Refer to Publication 967, The IRS Will Figure Your Tax, for complete information.

If you qualify for the earned income credit or the tax credit for the elderly or the disabled, we will figure it for you. However, there are certain requirements you must meet to qualify for these credits. Refer to Publication 596, Earned Income Credit, and Publication 524, Credit for the Elderly or the Disabled, to see if you qualify. Also, refer to Topic 601 for Earned Income Credit, or Topic 603 for Credit for the Elderly or the Disabled. Publication 967 provides details on what information you must provide us, such as which lines you must fill in and which forms you must complete and attach to your return. This publication also details the circumstances under which certain taxpayers do not qualify to have the IRS figure their tax.