Why is my federal tax deduction for state tax of over $6,000 only $602?

[bartlett004]

Turbo Tax says that a sales tax deduction  is better at over $1,000, but never shows or explains how the deduction for over $6,000 in state income tax is calculated. I can't find a way to calculate it on turbo tax or check it. It seems illogical that over $6,000 in state income tax is not worth more than $602 in deductions.

[MarilynG]

Go to FORMS mode (upper right) and open the Tax and Interest Deduction Worksheet, from either 'Forms in My Return' or by typing it into 'Open a Form' (screenshot).

Your Sales Tax total shows on Line 1f.  Your State Income Tax shows on Line 1h.  The box 'Greater Amount' should be checked below that.

The Total Taxes in this section flow to Schedule A, Line 5a.  Check your Schedule A to be sure the amount transferred (or click the Magnifying Glass to the left of the total to get there). 

If you are not using Itemized Deductions, though, this amount is not being used to calculate your Refund.

Here's more info:

https://ttlc.intuit.com/replies/6971774