Everyone knows the importance of April 15, but now there is a new date to add to your calendar: January 30, 2013.

That is the date the Internal Revenue Service will open the 2013 filing season and begin processing individual income tax returns, following  the January tax law changes made by Congress under the American Taxpayer Relief Act (ATRA).

The IRS will begin accepting tax returns on that date after updating forms and completing programming and testing of its processing systems. This will reflect the bulk of the late tax law changes enacted Jan. 2. The announcement means that the vast majority of tax filers — more than 120 million households — should be able to start filing tax returns starting Jan 30.

The IRS estimates that remaining households will be able to start filing in late February or into March because of the need for more extensive form and processing systems changes. This group includes people claiming residential energy credits, depreciation of property or general business credits. Most of those in this group file more complex tax returns and typically file closer to the April 15 deadline or obtain an extension.

The IRS will not process paper tax returns before the anticipated Jan. 30 opening date. There is no advantage to filing on paper before the opening date, and taxpayers will receive their tax refunds much faster by using e-file with direct deposit.

Who Can File Starting Jan. 30?

The IRS anticipates that the vast majority of all taxpayers can file starting Jan. 30, regardless of whether they file electronically or on paper. The IRS will be able to accept tax returns affected by the late Alternative Minimum Tax (AMT) patch as well as the three major “extender” provisions for people claiming the state and local sales tax deduction, higher education tuition and fees deduction and educator expenses deduction.

Who Can’t File Until Later?

There are several forms affected by the late legislation that require more extensive programming and testing of IRS systems. The IRS hopes to begin accepting tax returns including these tax forms between late February and into March; a specific date will be announced in the near future.

The key forms that require more extensive programming changes include Form 5695 (Residential Energy Credits), Form 4562 (Depreciation and Amortization) and Form 3800 (General Business Credit). A full listing of the forms that won’t be accepted until later is available on IRS.gov.