Yes, the $100,000 adds to your income. If your AGI for 2018 without this $100,000 of LTCG is $65,000 and you use the standard deduction of $24,000, your taxable income will be $141,000. $141,000 - $77,200 = $63,800 will be taxed at 15% LT capital gains rate, $100,000 - $63,800 = $36,200 will be taxed at 0% LT capital gains rate and $141,000 - $100,000 = $41,000 will be taxed as ordinary income. TurboTax will do all of these calculations for you on either the Qualified Dividends and Capital Gain Tax Worksheet or on the Schedule D Tax Worksheet.
