How can I see specifically how my refund was calculated?

[DoninGA]

Click on Tax Tools on the left side of the screen.  Click on Tools.  Click on View Tax Summary.  Click on Preview my 1040 on the left side of the screen.

[MollsBBU]

To preview your refund calculation before filing:

1. Sign in to TurboTax Online.
2. Next, click the Take me to my return button
3. Click Tax Tools from the black menu to the left
4. Then, select Tools
   To see the Tools option here, you must have moved past the orange "Take me to my return" button and you must be using a web browser (the mobile app will not show you the Tools feature)
5. Once in the tool center, click on View Tax Summary