No, you cannot deduct 401(k) contributions, regardless of their "kind". They are already reflected on your W-2 as pre-tax amount (box 12, usually code D). All you
have to do is report W2 data in Turbo Tax exactly as it appears on the form.
The 401(k)
plan contributions you elect to make come directly out of your salary. Since
the contributions are made with pre-tax dollars, your employer does not include
these amounts in your taxable income for the year. At the end of the year, when
you receive your W-2 form that shows your earnings, you will notice that your
wages subject to federal income (box 1) tax are lower because of your 401(k)
plan contributions (box 12). Since the contributions are not counted in your
taxable income to begin with, you do not take a deduction when you file your
return.
And yes, Roth 401K and Roth IRA are different in the way they are set up.... but neither is deductible on your tax return.
