Your AGI is not reduced by itemized or standard deductions. The AGI is arrived at earlier before Schedule A deductions are figured. Your AGI is on Page 1 of your Form 1040 before itemized/standard deductions even come into play. Deductions flow to Page 2 of the Form 1040. I'll tell you how to view the 1040 below.
Yes, TurboTax does all the calculations to determine whether you should itemize deductions or use the standard deduction. TurboTax starts off giving everyone the standard deduction, until the amount of entered deductions exceeds the standard deduction, then it switches over to itemized deductions.
You should enter all your deductions (medical, taxes, interest, donations, employee job expenses, etc.), and TurboTax will first determine if your standard deduction has been exceeded. TurboTax also determines how much of your medical expenses will count (if any.) After you enter the employee job expenses, TurboTax will do the calculation to see if your employee job expenses will count.
You can preview the Form 1040 at any time during preparation. Unfortunately you cannot view the other forms in online TurboTax unless you pay in advance for your return, which would give you viewing/printing privilege.
Here's how to preview the Form 1040 and a Tax Summary:
Log in and open your 2017 return if not already open. ("Take me to my return")
Once the return is open and past the blue-green screen, click on "Tax Tools" in the left menu column.
Then choose TOOLS.
In the Tools popup window choose "View Tax Summary."
Once the Tax Summary appears, review that Summary screen then go over to the left menu column again and choose "Preview My 1040" to bring up the actual 1040.
