How do I determine my IL-1040 amount for Line 1 if I was not required to file a federal return?

If you are not required to file a federal income tax return, use the U.S. 1040 as a worksheet to determine your adjusted gross income for Line 1 of the  IL-1040, Individual Income Tax Return

If you have additional inquiries, you may submit them to the Questions, Comments, or Request form.