How do I calculate tax for a non qualified Roth IRA distribution? My 1099-R form does not show the tax.

[dmertz]

The taxable amount is calculated on Form 8606 Part III.  After entering the Form 1099-R that reports the distribution from the Roth IRA, TurboTax will ask you to enter your basis in Roth IRA contributions and Roth conversions and use that information to complete Part III.