It's complicated. See the instructions for line 11 in the IRS instructions for Form 1040, beginning with "Line 11a" on page 38. Schedule 2 might also be involved. The instructions for Schedule 2 are on page 98. You can download the Form 1040 instructions from the following link.
https://www.irs.gov/pub/irs-pdf/i1040gi.pdf
One of the reasons you use TurboTax is so that you don't have to wade through pages of complicated instructions like this.