How does TurboTax calculate Form 8960 Line 9B?

[BobJ15]

The formula for Line 9b is:  (Total investment income) divided by (total adjusted gross income) multiplied by (state, local and foreign taxes).  Your total investment income is taxable interest (line 2b of 1040) plus ordinary dividends (line 3b of 1040) plus capital gains (line 13 of Schedule 1).  Note that Line 9b is zero if you do not itemize your deductions.

[jrj120]

Is this still the formula in 2022? That doesn't seem to match what Turbotax is doing for this line on my 2022 return.

[jrj120]

It is still the formula. The detail I missed is it is using State and local income taxes paid -- Line 5a on Schedule A. Not state and local taxes actually incurred.