NIIT Calculation Error

[rmlesnick]

Turbotax is using AGI minus threshold to calculate NIIT.  It should be using MAGI minus threshold.

[baldietax]

there are different MAGIs... have you checked Form 8960 instructions for Line 13

https://www.irs.gov/pub/irs-pdf/i8960.pdf

If you didn’t exclude any amounts from your gross income

under section 911 and you don’t own an interest in a CFC

or PFIC, your MAGI is your AGI as reported on Form 1040

or 1040-SR.