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Level 1

Net Investment Income on the "Est. Taxes and Form W-4 Wks"

Dear fellow TurboTaxers,


I would like to share a solution to a puzzlement that has troubled me for a few years now.  After your tax data is mostly entered, you might want to estimate your next year’s taxes.  TurboTax provides a lovely form ( and also asks the associated questions in the EasyStep mode) called “Estimated Taxes and Form W-4 Worksheet (ES & W4 Wks)”.   It has the current year values and lets you enter next year’s values (2019 and 2020 for this current and next year).  One of the entries on the form is the "Net Investment Income for 3.8% tax”; but I was never able to determine how they calculated this entry, my calculations don’t match their number, and TurboTax does not provide any clickable link.


Today I found where this number comes from:  Form 8960, Net Investment Income Tax - … (NIIT)   So, this form is NOT in the left hand column of my tax return list of forms because I am not subject to the NIIT.  BUT this is where they calculate the number for Net investment Income.  So now, finally I will be able to  estimate this number in the future.


TurboTax, please provide a link from form "ES &W4 Wks/Net Investment Income for 3.8% tax" to Form 8960.


My next trick is to figure out, on the same ES & W4 Wks form, where TurboTax gets the number for "Total of your other taxable income and losses” (again my numbers don’t add up to their number).  Again, if only they would provide a link to a form, or a list of what numbers they use, then I could match their calculation and estimate my numbers for the next year.